摘要:

OCTOBER, 1909. Vol. XXXIV., No. 4b3. THE ANALYST. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. THE SEPARATION OF MIXTURES OF SOME ALIPHATIC ACIDS BY MEANS OF BENZENE AND TOLUENE.* By T. R. HODGSON, M.A. 1 HAVE made a considerable number of experiments on the separation of mixtures of various fatty acids, with the object of finding out what degree of accuracy might be expected from Lasserre’s method (Annales de Z’lnstitut Pasteur, 1907, 829), and also whether the method might be in some cases useful for qualitative purposes. Varying weighed quantities of the pure fatty acids in question (formic, acetic, valeric, iso-valeric, etc.) were dissolved in water, and the solutions extracted with benzene. The hydrocarbon layer was then separated, and the proportion of acid in it and in the water determined, As the result of numerous experiments, it was found that in no case was the separation of the lower from the higher acids complete, the experi- mental errors, which were often considerable, varying with the amount of the acids taken, with the proportion of volatile solvent employed, and with the number of extractions.Similar experiments made with toluene gave results of precisely the same character. Light petroleum was also tried, but the results, although in some cases moderately good, were as a rule even worse than these obtained with benzene and foluene. Whilst it is evident that Lassere’s method cannot lay claim to any degree of accuracy as a means of separating the lower from the higher fatty acids, yet by due observance of conditions the results are in many cases sufficiently good to render the method one of some utility. I have found that the best results are obtained when a volume of benzene is employed equal to twice that of the volume of the acid solution to be extracted. THE CITY LABORATORY, B RI STO I,. * This work was carried ont in accordance with the terms of‘ the “Analytical Investigation Scheme.”

ISSN:0003-2654    

DOI:10.1039/AN9093400435

出版商:RSC    

年代:1909

数据来源: RSC

摘要:

436 THE ANALYST. EXPERIMENTS ON THE SEPARATION OF MIXTURES OF SOME ALIPHATIC ACIDS BY MEANS OF BENZENE.<: BY CHARLES A. KEANE, D.Sc., Ph.D., F.I.C., AND PERCIVAL NARRACOTT. A METHOD for the separation of formic and acetic acids from normal and iso-butyric acids and from normal and iso-valeric acids was described by A. Lasserre (Annales de Z’Institut Pasteur, 1907, 829). The method is dependent upon the extraction of the aqueous solution of mixtures of these acids with benzene. Formic and acetic acids are said to remain in the aqueous solution whilst their higher homologues are extracted by the benzene. After the separation of the two solutions, the acids in each are respectively converted into their barium salts and weighed, and the latter then decomposed with the formation of barium sulphate.Data are thus obtained from which the proportions of the several acids are determined by indirect calculation. The results appended to the description of the method are only approximate. Most of them are low, and the error ranges from 1.3 up to 17 per cent. on the weight of acid taken for analysis. Apart from the inevitable lack of accuracy in the application of an indirect method of analysis to salts which do not differ greatly in their molecular weights, as. made use of for the estimation of the acids subsequent to their separation by means of benzene, no data are given of the ratios of distribution of the acids between water and benzene, on which the validity of the method obviously depends. In view of the importance to analysts of a reliable method for the analysis of mixtures of such acids as the above, the following determinations of these distribu- tion ratios were made with the object of ascertaining the reliability of this portion of the method, and with the view of modifying the subsequent procedure should the initial process of separation prove satisfactory.METHOD OF EXPERIMENT. Solutions of the acids in water were made, so that the volume used for the determination contained in all cases approximately 1 grm. of acid. The concentra- tions of these solutions were determined by titration with The volume of acid solution was placed in a separating funnel, the benzene added, and the liquids thoroughly agitated for five minutes. The layers were then allowed to separate, the lower aqueous layer run off, with careful draining, and the contained acid titrated with sodium hydroxide. The benzene solution was titrated in all cases as a check.sodium hydroxide. All experiments were made in duplicate. * This work was carried out in accordance with the terms of the “ Analytical Investigation Scheme.”THE ANALYST. 437 RESULTS. Series 1.-Ratio of Volume of Aqueous Solution used to that of Benzentf=1 : 1. Quantity of Acid in Aqueous Layer=l grm. Distribution Ratios. Water. Benzene. Formic acid ... ... ... ... 1 : 0.0242 Acetic acid ... ... ... ... 1 : 0.0267 Propionic acid ... ... ... ... 1 : 0.1290 n-Butyric acid ... ... ... ... 1 : 0.7585 Iso-butyric acid ... ... ... ... 1 : 0*8100 Iso-valeric acid ... ... ... ... 1 : 2,7440 Series 2.-Ratio of Volume of Aqueous Solution used to that of Benzeize=1 : 10.Distribution Ratios. Quantity of Acid in Aqueous Layer = 1 grm. Water. Benzene. Formic acid ... ... ... 1 : 0.056 Acetic acid ... ... ... ... 1 : 0.445 n-Butyric acid ... ... ... ... 1 : 8-710 Iso- butyric acid ... ... ... ... 1 : 13.010 Iso-valeric acid* ... ... ... ... 1 : 43.820 ... Series 3.-Ratio of Volume of Aqueous Solution used to that of Benzene=10 : 1. Distribution Ratios. Quantity of Acid in Aqueous Layer = 1 grni. Water. Benzene. Formic acid ... ... ... ... 1 : 0.0022 Acetic acid ... ... ... ... 1 : 0.00297 n-Butyric acid ... ... ... ... 1 : 0.1110 Iso-butyric acid ... ... ... ... 1 : 0.1377 Iso-valeric acid ... ... ... ... 1 : 0.5920 CONCLUSIONS. Taking the first series of results, it will be seen that, even in the case showing the greatest difference in solubility in benzene under the conditions of experiment- viz,, that of formic (or acetic) and valeric acids-the latter is only about one hundred times more soluble than either of the former.The use of a large excess of benzene, as in Series 2, shows that a, better separation of these acids can be effected, but it does not render the method applicable to any other mixtures; when the water is in excess, as in Series 3, the differences in solubility are similar in character, but iso-valeric acid is only about two hundred times more soluble in the benzene than acetic acid. The distribution ratio of acetic acid in Series 2 is remarkably different from that in Series 1. This is in accord with the results published by Herz and Fischer (Bey., 1905, 38, 1138), who have shown that this ratio is dependent upon the con- centration, and varies within such wide limits as from 0.0274 to 0.1294 according to this factor, using equal volumes of the solvents, but varying the concentration of the acid.In Series 2 the concentration of the acid is greater than in Series 1, owing to * Volume used contained only 0'44 grm. acid owing to its slight solubility in water.438 THE ANALYST. the greater proportion of benzene, in which the acetic acid is less soluble than in water. This effect is to be attributed to the molecular association of the acetic acid. The following additional determinations were made, using a mixture of two acids in each case, the quantity of each being known, and the number of C.C.of sodium hydroxide solution required for neutralisation, therefore, being also known. After shaking the volume of mixed acid solutions with an equal volume of benzene, both the benzene and aqueous solutions were titrated. The results obtained in the titration of the benzene solutions were as follows : 1. Formic and Iso-Vuleric Acids.-Benzene layer required 3 C.C. NaOH. Number of C.C. required, as calculated from above distribution ratios, = 3-3 C.C. 2. Acetic and Iso-”aleric Acids. -Benzene layer required 3.3 C.C. NaOH. Number of C.C. required, as calculated from above distribution ratios, = 3.3 C.C. These results show that the distribution ratios of the acids between benzene and water is maintained in a mixture of acids, and that the separation of such mixtures should be effective were the respective solubilities favourable. From these experiments it is clear that the method suggested by Lasserre does not rest upon a satisfactory basis of separation, and that the results must vary with the proportions and concentrations of the acids present. Investigations for the separation of the acids by other methods are in progress. c H EhIISTItY DEPARTMENT, THE SIR JOHN CAW TECHNICAL INSTITUTE, ALDGATE, LONDON, E.C. ? & * @ & + I 3

ISSN:0003-2654    

DOI:10.1039/AN9093400436

出版商:RSC    

年代:1909

数据来源: RSC

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438 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. Acids of the Pineapple. R. Kayser. (Zeit. oferttl. Chem., 1909,15,187-188.)- 'The author records the following analysis of the freshly expressed and filtered juice .of the pineapple (two samples of different origin) : I. Grms. per 100 C.C. 11. Grms. per 100 C.C. Dry solids ... ... ... ... Invert sugar . . . ... ... ... Cane sugar ... ... ... ... Citric acid ... ... ... ... Tartaric acid Malic acid } Ditto expressed as citric acid ... ... Total acidity (as H,SO,) ... ... ... 16.72 4.00 8.64 0.63 absent 0.446 0.582 16.14 3-20 9-10 0.60 absent 0.444 0,579 Only a small proportion of the citric acid, therefore, is in combination with bases. J. F. B.THE ANALYST. ' I Bambarra,, Groundnut& 439 Seeds of '( Hibis- cus Sabdariffa." Some African Food Grains. following analyses are given : Moisture .. . . . . . . . Ash . . . . . . . . . Fat . . . . . . . . . . . . Fibre ... Albuminoidi (N ~'6.25) ... Starch, etc. (by difference) Nutrient value . . . . . . Nutrient ratio . . . . . . Grey Millet. Per Cent. 11.2 1 -9 4-0 1 *2 8 -2 73'4 90.8 1 : 10.0 Bulrush Millet. Per Cent. 11.3 2.0 3 -3 1-5 10.4 71 5 89.5 1 : 7.6 (Bull. Imperial Inst., 1909, 7, 145-154.)-The Italian Millet. Per Cent. 10.2 1.2 2.9 1 *5 10.8 73.4 91.0 1 : 7'4 Tamba Millet. Per Cent. 12.8 2.2 1.3 3.4 5.3 75.0 83.2 1 : 14.5 '( Bolu " Grain. Per Cent. 14.0 2.8 1'1 3.0 6.2 72.9 82.0 1 :12*0 I Per Cent. 13.1 2.4 6.2 3.9 16.0 58.4 85.5 1 : 4.5 Per Cent. 7'4 5.0 19'8 15-5 26-8 other N-com- pounds, trace (P,O,= 39'7%) 25-2 97.5 1 : 2.6 A.R. T. Analysis of Milk or Cream Chocolate. E. Baier and P. Neumann. (Zeit. Untersuch. Nahzr. Genzissm., 1909, 18, 13-27.)-The quantity of milk or cream in a sample of chocolate may be ascertained by estimating the quantity of milk-fat and casein present ; the percentage of butter-fat is found from the Reichert-Meissl value of the fat separated from the chocolate, and the amount of casein is estimated by a modification of Hammarsten's method, which depends on the solubility of casein in ammonium oxalate solution and on the insolubility of other proteins in this solution. The authors find, however, that whilst casein is not completely soluble in ammonium oxalate solution, it is in sodium oxalate. The estimation of the casein is carried as follows: 20 grm.of the powdered chocolate are extracted for sixteen hours with ether in a Soxhlet apparatus ; the extracted residue is allowed to dry spontaneously, and 10 grm. of it are then rubbed down in a mortar with a small quantity of 1 per cent. sodium oxalate solution. The paste is washed into a 250 C.C. flask, with about 200 C.C. of the oxalate solution, the mixture is heated to boiling, and hot sodium oxalate solution is added so as to fill the flask nearly up to the mark. After standing for about eighteen hours, with occasional shaking, the mixture is diluted with cold sodium oxalate solution t o a volume of exactly 250 c.c., mixed, and filtered, To 100 C.C. of the filtrate 5 C.C. of 5 per cent. uranium acetate solution are added, and 30 per cent.acetic acid is then run in drop by drop, with constant stirring, until the casein commences to be precipitated. From 30 to 120 drops are required, according to the quantity of casein present. Five drops of the acetic acid are added in excess, the precipitate is separated by centrifugal action, and washed with a solution containing 5 grm. of uranium acetate and 3 C.C. of 30 per cent. acetic acid per 100 C.C. When the washings no longer give a reaction for oxalates, the precipitate is transferred to a flask, and the quantity of nitrogen in it estimated by Kjeldahl's process. The nitrogen found multiplied by 6.37 gives the amount of casein, which is then calculated into a percentage quantity on the original chocolate. In calculating the percentage of milk-fat, it is assumed that cacao440 THE ANALYST.butter has a, Reichert-Meissl value of 1.0, and milk-fat a value of 27.0. The total milk solids present in the chocolate may be calculated from the quantities of casein and fat found; the constituents forming these solids being fat, protein, lactose, and mineral matter. The protein is obtained by multiplying the casein by 1.111, the lactose by multiplying the protein by 1.3, and the mineral matter by multiplying the protein by 0.21. A simple calculation will give the fat content of the milk or cream used in the preparation of the chocolate. The authors consider that the milk employed should contain about 3.5 per cent. of fat, and the cream about 10 per cent. Milk chocolate should contain at least 15 per cent.of dry milk solids, and cream chocolate at least 20 per cent. of dry cream solids. W. P. S. Estimation of Extractive and Glyeerin in Spirituous Galenicals. W. A. H. Naylor and E. J. Chappel. (Pharm. Journ., 1909, 83,139-141.)-1n the estimation of glycerin in pharmaceutical preparations by the distillation method, it is not easy to drive over all the glycerin from the distillation flask ; moreover, if a rubber stopper be used it is liable to retain an appreciable quantity of the glycerin in the form of condensed drops. The authors employ a special distillation flask with a very short, wide neck, fitted with a ground-glass stopper through which pass two tubes. One tube reaches to the bottom of the flask, and is connected with a steam coil which is immersed in the bath in which the distillation flask is heated; the other tube conducts the distilled vapours to a set of two Wsulff's bottles in which they are collected for estimation.Five C.C. of the extract are placed in the distillation flask, and the apparatus is placed under a reduced pressure of 180 to 200 mm. The temperature of the bath, in which the flask is almost totally immersed, is raised to 130" to 140' C., and the alcohol and water are distilled off in a slow current of washed air. After this, steam is admitted through the heated coil, very gently at first, to avoid splashing, and the distillation with steam is continued for about three hours. Any glycerin which may have condensed on the stopper of the flask is washed into the Wou1ff"s bottle for titration.The distillate is concentrated to a small bulk, filtered, diluted to a known volume, and the glycerin estimated by the bichromate method. The extract remaining in the flask is dried and weighed. J. F. B. Detection of Starch Syrup in Honey and Fruit Juices. J. Fiehe. (Zeit. Untersuch. Nahr. Genussm., 1909, 18, 30-33.)-The following test is proposed for the detection of starch syrup (dextrin) in honey, etc. I t depends on the fact that starch dextrin is precipitated by alcohol in the presence of hydrochloric acid, whilst honey dextrins remain soluble. The honey solution (1 : 2) is heated on the water-bath and treated with tannin solution ; this precipitates protein substances. After standing for twelve hours the solution is filtered, and to 2 C.C. of the filtrate are added 2 drops of concentrated hydrochloric acid (sp.gr. 1-19) and 20 C.C. of 94 per cent. alcohol, In the case of pure honey the solution remains perfectly clear ; should achroo-dextrins be present, a milky turbidity is produced, whilst starch dextrin gives a strong turbidity, or even a precipitate. The test must be slightly modified in order to detect dextrin in fruit juices, as theTHE ANALYST. 441 latter contain calcium salts of organic acids which may be precipitated by alcohol in hydrochloric acid solution. Ten C.C. of the juice are diluted with an equal volume of water, 5 drops of 10 per cent. ammonium oxalate solution are added, the mixture is boiled, a little animal charcoal is added, and the whole is again boiled and filtered. TWO C.C.of the filtrate are then treated with hydrochloric acid and alcohol as described in the case of honey. Experiments with pure honeys and fruit juices and mixtures of the same with starch dextrin showed that the test will detect the presence of about 5 per cent. of the latter substanco. w. P. s. Determination of Gingerol in Ginger. H. Garnet and J. Grier. (Pha7m. Jozirn., 1909, 83, 159-160.)-The authors have made a number of experiments with a view to ascertain the most favourable conditions for the extraction of gingerol, the active phenolic principle o€ ginger, in as pure a form as possible. Attempts to fix the resinous impurities by a preliminary treatment with alkaline substances led to no satisfactory result. Certain solvents, such as light petroleum, and acetone (by cold percolation), do not afford a complete extraction of the gingerol.Alcohol of 50 to 60 per cent. strength extracts the gingerol together with other extractive substances of a gummy nature. Pure ether, free from water and alcohol, and pure alcohol, afford a complete extraction of the gingerol, but this is accompanied by fatty and resinous impurities. When petroleum spirit is used, the gingerol may be removed from the extract by shaking the latter with 60 per cent. alcohol. The alcohol is then evaporated off and the aqueous residue shaken with ether. The authors think that ether is probably the best solvent for extracting the gingerol, the ether being evaporated and the residual extract boiled out several times with successive portions of petroleum spirit.The filtered solution is then treated as above with 60 per cent. alcohol. In the final shaking out, carbon bisulphide or chloroform may be used instead of ether ; a drop of dilute hydrochloric acid at this stage greatly assists the separation of the liquids. Jamaica ginger contains about 1.1 per cent. of gingerol, and African ginger about 2 per cent. J. F. B. Detection of Papua Mace. C. Griebel. (Zeit. Unterszich. Nahr. Ge?zzissm., 1909, 18, 20%206.)-Papua or Macassar mace is obtained from Myristica argentea, New Guinea; it contains about the same amount of aromatic substances as does Banda mace, but the aroma is different, and whilst Banda mace yields from 20.8 to 27-9 per cent. of dr fixed ether extract other than essential oil, Papua mace gives from 534 to 55.5 per cent.I t is mixed with Banda mace by spice-dealers, and such mixtures are found on the market ; more correctly, it may be said that Banda mace is added to Papua mace, as the latter, on account of its high oil content, is difficult t o grind without the addition. To detect the presence of Papua mace in ground mace (Banda) the following test is given : 0.1 grm. of the mace under examination and the same quantity of pure Banda mace are placed in test-tubes and shaken for one minute with 10 C.C. of petroleum spirit. The solutions are then filtered, and 2 C.C. of each filtrate are mixed with 2 C.C. of glacial acetic acid in separate test-tubes. Concentrated sulphuric acid is carefully added to both tubes SO as to form a layer under the acetic acid solution.If the sample contains Papua mace, a red ring forms442 THE ANALYST, at the junction of the two liquids, whilst pure Banda mace yields a yellow zone. The coloration develops in the course of a minute or two ; after this time Banda mace may give a similar coloration, hence the necessity of the comparison test with Banda mace. Bombay mace, when similarly treated, yields a colourless zone. By using twice the quantity of petroleum spirit it is posoible to defect the presence of as little as 10 per cent. of Papua mace in a mixture, but the coloration takes longer to develop. However, upwards of 20 per cent. of Papua mace is usually present in such mixtures, for the reason stated above, and the former test is more reliable. It is impossible to detect the admixture by examination with the microscope, but, when.in the whole condition, Papua mace is readily distinguished from Banda mace. w. P. s. Estimation of Phenolphthalein in Pharmaceutical Preparations, K. Kollo. (Apoth. Zeit., 1909, 283; through J. Pharm. Chim., 1909, 30, 174-175.)- The following methods of estimation are described: (1) A known weight of the dried and finely powdered material is extracted with pure acetone (boiling-point 56O-57" C.), until the extract no longer gives a pink coloration with sodium hydroxide ; the extract is evaporated in a tared flask, and the residue dried at 100" C., and weighed. (2) The powdered substance is extracted with an 8 per cent. solution of sodium hydroxide, and the phenolphthaleln precipitated by means of acetic acid. The precipitate is washed with water, and dissolved off the filter by means of acetone, the solution evaporated, and the residue dried at 100" C., and weighed.(3) The solution of the phenolphthalein in 8 per cent. sodium hydroxide solution is treated, drop by drop, with a solution of iodine (2 grm. of iodine, 3 grm. of potassium iodide, 200 C.C. of water), which changes the colour first to blue and then to yellow. The phenolphthalein tetra-iodide thus formed is collected on a tared filter, washed with alcohol and with ether, and dried at 100' C., and weighed. One gram of the tetra- iodide corresponds to 0.3869 grm. of phenolphthalein. (4) The phenolphthalein is extracted with acetone, and acetylated by means of acetic anhydride. The acetyl derivative is then saponified by means of an alcoholic solution of sodium hydroxide, the excess of which is subsequently titrated.Each C.C. of N-sodium hydroxide solution corresponds to 0.400 grm. of the acetyl derivative, and to 0.318 grm. of phenolphthalein. C. A. If. Separation of Strychnine from Brucine. G. Pinchbeck. (Pharm. Journ., 1909, 83, 144-145.)-The author shows that the method for the separation of strychnine from brucine, based on the oxidation of the latter alkaloid by nitric acid and the subsequent recovery of the strychnine, is intimately dependent on the presence of nitrogen peroxide in the acid employed. When pure nitric acid is used, no red coloration is produced. Consequently the oxidation of the brucine may be assisted by the intentional introduction of the lower oxides of nitrogen, and the author proposes to make use of a reagent prepared by diluting the commercial fuming nitric acid with commercial white nitric acid in such proportions that the mixture contains 1 per cent.of nitrogen tetroxide and not less than 70 per cent. of absolute nitric acid. With this reagent a red coloration is immediately developedTHE ANALYST. 443 in presence of brucine, and the intensity of the colour is far greater than in ordinary circumstances. A weighed quantity of the alkaloids is dissolved in 15 C.C. of 3 per cent. sulphuric acid, and the temperature is raised to 25' C. ; 1.5 C.C. of thig special nitric acid are added, and the mixture is set aside for fifteen minutes. Excess of sodium hydroxide is then added, the strychnine is shaken out with chloroform three times, and recovered according to the U.S.P. method. If ammonia or sodium carbonate be used for liberating the alkaloid, the strychnine residue is too high. If the oxidation be allowed to proceed for a longer time than is indicated above, a loss of strychnine will take place. In order to avoid loss of strychnine by decrepitation, the chloroform extract should be evaporated to a volume of 1 c.c., 2 C.C. of amyl alcohol should be added, and the liquid evaporated in a current of warm air, the residue being dried at 110" C., with a cap of filter-paper over the mouth of the flask. The percentage of nitrogen tetroxide in the acid may be determined by running the acid slowly from a burette into standard permanganate at a temperature of 40" c. J. F. B.

ISSN:0003-2654    

DOI:10.1039/AN9093400438

出版商:RSC    

年代:1909

数据来源: RSC

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THE ANALYST. 443 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Simple Method for Differentiating between Human and other Blood. Piorkowsky. (Gaz. Mddic. d e Paris, 1909,ll; through Phurm. Jouryz., 1909,83,240.) -One drop of fresh blood, diluted with 10 to 50 drops of water, is carefully poured on to the surface of 1 C.C. of hydrocele fluid or human blood serum (preferably the former), contained in a test-tube 6 cm. long and 8 min. in diameter. If the blood is of human origin, a faintly red coloured precipitate of coagulated blood makes its appearance in about half an hour, the supernatant liquid remaining clear. I n the case of blood from the lower animals, no precipitate is produced, while the liquid is coloured red. Dry blood is first dissolved in physiological salt solution before applying the test.A. R. T. New Method of Estimating Quinine, and Elimination of that Alkaloid in the Urine, M. Nishi. (Arch. exper. Pathol. u. Pharmakof., 1909, 312; through J. Pha,rm. Chirn., 1909, 30, 112-113.)-The method is based upon the fact that, on treating an ethereal solution of quinine with an ethereal solution of citric acid, the alkaloid is precipitated in the form of an acid citrate (C2,H2,02N2,C,H,07), which is insoluble in ether. The method may be used for the estimation of quinine in urine, and satisfactory results may be obtained by rendering the urine alkaline and extracting the alkaloid with ether. I n this way the author found that, on taking a dose of 0.5 grm. of pure quinine, 34.45 per cent. thereof could be recovered from the urine in seventy-two hours, the bulk (25.5 per cent.) having been eliminated from the system during the first day.The addition of arsenic or iron to the quinine does not appear to have any influence on the absorption or the elimination of the alkaloid, or to affect its decomposition in the organism. C. A. M. Action of the Bacillus Bulgaricus on Various Sugars. G. Bertrand and F. DuchaGek. (Biochenz. Zeib., 1909, 20, 100-112.)-The Bacillus bulgariczis, which ferments milk to form the Bulgarian beverage ‘‘ Yoghurt,” cannot be cultivated444 THE ANALYST. readily in other media without losing its biochemical characteristics. The authors have therefore investigated the action of the organism on various sugars, with the view of finding a suitable medium, other than milk, in which it may be grown.Of the reducing, non-hydrolysable sugars, dextrose, galactose, fructose, and mannose are fermented by the bacillus, whilst arabinose, xylose, and sorbose are not attacked. Of the hydrolysable sugars only lactose is fermented ; sucrose and maltose withstand the action of the organism. In every case where fermentation takes place the products formed are the same-namely, large quantities of d- and I-lactic acid, together with small amounts of formic, acetic, and succinic acids. These products are also formed when the organism is grown in milk, but the proportions are different. When artificial sugar media are fermented, exactly equal quantities of d- and I-lactic acid are formed, and the mixture is optically inactive; but in the case of milk, less I-lactic acid is produced, so that the excess of d-lactic acid causes the mixture to be destro-rotary.Possibly the other constituents of the milk interfere and produce the difference. Peptonised malt extract, with the addition of calcium carbonate and lactose, was found to be a suitable medium for Mannite is not converted into lactic acid. the cultivation of the organism. w. P. s. Estimation of Glycuronic Acid in Urine by Means of the Furfural- Hydrochlorie Acid Distillation Method. C. Tollens. (Zeit. yhysiol. Clzem., 1909, 61, 95-lll.)-Glycuronic acid, when distilled with hydrochloric acid, yields furfural, which may be estimated by condensation with phloroglucinol, and the method proposed is based on these reactions. Two hundred and fifty C.C. of the urine are treated with 150 C.C.of basic lead acetate solution and 5 C.C. of ammonia, and, after the lapse of several hours, the clear supernatant liquid is poured through a double, hardened filter-paper. The precipitate is washed with about 750 C.C. of water, and the filters and precipitate are then placed near a fire or other source of heat, so that they may dry slowly. This precipitation of the glycuronic acid is necessary in order to remove substances present in urine which interfere with the formation of furfural when the distillation with hydrochloric acid is carried out. As goon as Ehe precipitate is sufficiently dry to allow the filter-papers to be separated, the precipitate and inner filter are transferred to the distillation-flask, the other filter being used to wipe out the funnel; it is also introduced into the flask.After the addition of 100 C.C. of hydrochloric acid of sp. gr. 1-06, the contents of the flask are distilled; when 30 C.C. of distillate have been collected, a further 30 C.C. of the hydrochloric acid are added to the flask, and so on, until a drop of the distillate no longer yields a coloration with a drop of aniline acetate solution placed on a filter- paper (see ANALYST, 1899, 24, 179). Generally s negative reaction is obtained when about 400 C.C. of distillate have come over. A solution of about 0.25 grm. of phloroglucinol in hydrochloric acid is added to the total distillate, which must be diluted to a volume of 400 C.C. with the hydrochloric acid if this quantity of distillate has not been collected.The precipitate formed is collected on a weighed filter after the lapse of at least sixteen hours, washed with 150 C.C. of water, and weighed after being dried at a temperature of 100' C. for four hours. The weight of furfural-phloro- glucide found, multiplied by three, gives the quantity of glycuronic acid. To theTHE ANALYSTo 445 quantity thus found is added 0.0052 grm. to correct for the solubility of the compound in the 550 C.C. of solution and wash-water. The quantity of glycuronic acid in normal urine is about 0.5 grm. in the total volume passed per diem; it is considerably increased by the administration of terpine hydrate and sodium salicylate. The amount of glycuronic acid in urine may also be determined colorirnetrically by freating 5 C.C. of the sample with 0.5 C.C. of a 1 per cent. alcoholic solution of naphtho- resorcinol and 5 C.C. of hydrochloric acid of sp. gr. 1.19. The mixture is boiled for one minute, allowed to stand for four minutes, then cooled under a stream of water, and shaken with 10 C.C. of ether. After standing for one minute, 0-5 C.C. of alcohol is added, and the coloration produced is observed. If the latter be intense, the urine is diluted, and the test repeated, the same concentration of reagents being employed, until a test is obtained which just shows a coloration. The volume of urine used in the test will then contain from 0.5 to 1.0 mgm. of glycuronic acid, as this quantity just yields an appreciable coloration. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9093400443

出版商:RSC    

年代:1909

数据来源: RSC

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THE ANALYST, 445 ORGANIC ANALYSIS. Detection of Methyl Alcohol in Ethyl Alcohol. A. Vorisek. ( J . SOC. Chenz. I.rzcZ., 1909, 28, 823-825.)-The test proposed consists in oxidising the alcohols with chromic acid, distilling, and testing the distillate for formaldehyde. About 1 C.C. of the alcohol or alcoholic distillate is placed in a test-tube, 1 C.C. of 0-8 per cent, solution of chromic acid (free from sulphuric acid), 3 or 4 C.C. of water, and a fragment or two of pumice, are added, and the mixture is distilled ; a, long bent-glass tube, fitted into the test-tube by means of a cork, serves as a condenser. About 4 C.C. of distillate are collected in another test-tube, and tested for the presence of formaldehyde by the method described by Hehner (ANALYST, 1896,21, 96). The author employs a dilute solution of egg-albumin in this test, but milk was found to answer nearly as well.The test will detect as little as 0.001 grm. of inethyl alcohol in 1 C.C. of ethyl alcohol (cf. Hinkel, ANALYST, 1908, 33, 417). w. P. s. Saponification of Carnauba Wax. R. Berg. (Chenz. Zeit., 1909, 33, 885- 887.)-The author finds that carnauba wax is more rapidly saponified when xylene is used as the solvent than when alcohol is employed. Four grams of the wax should be dissolved in 20 C.C. of pure xylene, and the acid value determined as usual by titration with alcoholic potassium hydroxide solution. An excesg of the latter solution is then added, and the mixture is heated on a boiling water-bath and under a reflux condenser for two hours. At the end of this time 100 C.C.of alcohol are added, the mixture is boiled, and the excess of alkali is titrated back. Working in this way, two samples of carnauba wax were found to have saponification values of 87.89 and 87.05 respectively. When alcohol alone waB used identical values were obtained, but only after twenty-four hours’ boiling. w. P. s. Amount of Free Nicotine (Bases) in Tobacco Smoke. J. Toth. (Chem. Zeit., 1909,33, 866-867.)-1n the author’s experiments 300 cigars were successively burned, and the smoke aspirated through two cylinders filled with cotton-wool, and finally446 THE ANALYST. New York State. through water, The cotton-wool was afterwards extracted, first with ether, then with alcohol, and then with water, the extracts evaporated, and the amount of nicotine estimated by titration in the residues before and after being treated with alkali, the difference between the two results giving the amount of combined bases.The results showed that the smoke from the 300 cigars contained 8.786 grm. of free bases calculated as nicotine, and 0-661 grm. of combined organic bases calculated as nicotine; or, in other words, that the bulk (93 per cent.) of the organic bases in tobacco smoke is present in the free state. C. A. M. Michigan Japanese State. Normal Oil. Samphire Oil. F. Borde. (BUZZ. des Sci. Pharm., 1909,132; through Pharm. Joumz., 1909,83, 240.)-The oil obtained by steam-distillation of the stalks and leaves of Cdhmum maritinzunz, or samphire, is heavier than water, of a deep yellow colour, aromatic odour, and slightly acrid ; that from the fruits is light yellow in colour, and has a more pleasant odour than the firfit-named oil.The yields vary with the time of collection, being from 1.5 to 3 grm. per kilo in the case of the former oil, and 7 to 8 grm. per kilo in the case of the fruit oil. The oil from the dried fruits had the following characters : Sp. gr., 0.950 to 0.980 ;* boiling-point, 170" to 300" C. ; [a], = 5-27" to 8.15'; iodine number, 174 to 200; saponification value, 4 to 10; acetyl value, 3 to 4; solubility in 90 per cent. alcohol, 1 in 6 ; in 'TO per cent. alcohol, 1 in 30. A. R. T. Specific gravity" O p t i c a l r o t a - Menthol, free, % Menthol a s Menthol, total, S o l u b i l i t y i n tion t esters, % % alcoh 01 Peppermint Oil. (BUZZ. Imperial Inst., 1909, 7, 184-193.)-The following table shows the composition and properties of American, English, and Japanese oils : 0.900 to 0.91C - 23" ,, -33' 50 ,, 60 3 ,, 14 58 ,, 66 - English.3.910 to 0.920 - 25" ,, -33" 40 ,, 45 8 ,, 14 50 ,, 60 Not in 70 %, solu- ble in 4 vol- ume or more of 90 % alco- hol 0.995 to 0,913 0.895 to 0.900 - 18" ,, - 29' - 30" ,, - 42" 43 ,, 50 48 ,, 58 65 ,, 85 4.3 ,, 8.5 J J 70 ,, 91 solubleSoluble in 4Soluble in 3 to 5 parts of to 5 parts of 70 % alcohol 70 %alcohol Japanese Oil from which Menthol has been removed. 1-895 to 0.905 - 20' ,, - 35" 34 ,, 44 6 1 , 11 43 ,, 50 Not always soluble in 70 % alcohol A. R. T. * Temperature not stated. I- Length of observation tube not stated.THE ANALYST. Paraffin. 447 Oil. Examination of Paraffin Wax.L. Singer. (Petrolezim, 1909, 4, 1038- 1040.)-ShukofP s reference method (Chenz. Rev. Fett- W. Ham-Id, 1899, 6, 11) of determining the solidification-point of paraffin wax is now almost universally employed in commercial transactions in Austria and Hungary. Attempts have frequently been made to establish a relationship between the so-called " oil content" and the external appearances of a wax, and even those manufacturers who formerly preferred opaque products now put a greater value upon transparent waxes, which they regard as free from oil." For the estimation of the " oil," Holde's method is frequently used : A solution of 0.5 grm. of the paraffin wax in 30 C.C. of ether is mixed with 30 C.C. of 96 per cent. alcohol, and the mixture cooled to 20" C.and filtered. The deposit is washed with 10 C.C. of a mixture (1 : 1) of alcohol and ether at 20" C., and dissolved off the filter by means of hot benzene or petroleum spirit ; the solution is evaporated in a tared basin, and the residue dried at 105" C. and weighed. The filtrate and washings are also evaporated, and the residue washed with 6 C.C. of the alcohol-ether (this time cooled to -20" C.), dried, and weighed. I t s amount added to that of the first precipitate gives the quantity of paraffin in the sample. Finally, this last filtrate is evaporated, and the weight of the residue gives the proportion of 6 6 oil" in the paraffin wax. In the case of hard paraffins, an addition of 1 per cent. should be made to the result thus obtained. If the residue is dissolved in 10 C.C.of petroleum spirit, and the solution again treated with alcohol and ether as in Holde's method, the proportion of oil will be consider- ably lower. Typical results obtained by the author are shown in the following table in comparison with the solidification-points in the Shukoff test : 90.02 98.10 98.93 99-55 Grade. 9-98 1.90 1.07 0.45 White, soft (matsch) ... ... 50/51, opaque ... ... ... 50/51, transparent.. . ... ... 60, transparent ... ... ... solidifica- tion- Point ("(2.). 44.9 50.3 50.6 58.6 Without Petroleum Spirit. With Petroleum Spirit. Paraffin. 91.90 99.80 99.78 100*00 Oil. 8-10 0.20 0.22 0.00 These figures show that the amount of 6 ' oil " in transparent and opaque samples of paraffin wax of the same grade may be approximately the same.One transparent eample thus examined yielded as much a8 3.6 per cent, of oil. These results dis- prove the commonly accepted view that transparency necessarily implies freedom from " oil,'' and that transparent waxes are of better quality than opaque waxes. Analogous results were obtained by Zaloziecki's method of dissolving a paraffin wax or paraffin oil in amyl alcohol, and precipitating the paraffin by means of ordinary alcohol. Since all the paraffin waxes examined (including American and peat paraffins) were found to contain oil," the author suggests the adoption of a standard for the permissible '' oil-content " of commercial samples. In most cases the upper418 THE ANALYST- limit might be fixed at 2 to 24 per cent., an exception being possibly made in the case of soft paraffin waxes for matches. Another difficulty in the examinationof paraffin wax is the want of agreement in the methods of grading in usein different countries, and there is need of a table giving the relationship between the Shukoff's figures and the results obtained by the Scotch and American methods.The following table gives the present corresponding values, but the author has found them incorrect : German Method ("C.). Scotch Method ( O F . ). American Method ( O F . ) . 38/39 45/46 48/49 50151 51/52 53/54 56/57 981102 1151 118/120 125/127 1301 110/112 1181120 101/105 1131115 1211123 1211123 1281130 1331 1181 C. A. M. Rubber from Southern India. (BUZZ. Imperial Inst., 1909, 7, 163-166.)-The following analyses of rubbers prepared from Ceara, Castilloa, and Para trees growing at Kullar and Burliar, in the Nilgiri Hills, are given.The resin figure represents the acetone extract of crude rubber. Soluble caoutchouc is that portion of crude rubber insoluble in acetone, but soluble in chloroform ; and insoluble caoutchouc the portion of crude rubber insoluble in acetone and chloroform, and matter, etc. corrected for dirt, mineral Ceara Rubber.. Manihot Glaziovza) Castilloa Rubber (C. elastics). Para Rubber (Hevca Bratiliensis). 11. TI. I. 1. Dry. Per Cent. __ 76 -5 6-0 6 . 4 9.8 1.3 - Dry. Per Cent. - 63.6 32.5 0.9 3.0 2.4 Dry. Per Cent. 86.2 12'9 0.6 0'4 - - Dry. Per Cent. - 88.8 4-0 2% 3 '0 1'6 - Dry. Per Cent. 90.0 1 '9 3.9 3.7 0 -5 - - AS Received. As Received. Per Cent. 15 i. 62.7 32.0 0 69 2-9 2.29 As Received. A s Received. Per Cent. 0 *8 ) 92.0 2.6 3.0 1% - As Received. Per Cent. 0.4 191.5 3.9 3.7 0.5 - Per Cent. 2 -8 80.2 6 '2 9.5 1-3 - Per Cent. 0-2 ) 86.1 12.8 0.5 0'4 - Moisture ... ... Sol. caoutchouc Insol. caoutchouc 1 Resin ... ... Protein ... ... Insol. matter ... Ash ... ... Soft and sticky. Physical properties : Very good. Stronger than and superior t o I. Rather deficient in strength. Fair strength. A. R. T.THE ANALYST. 449 distillation-tube shown in Fig. 1. It consists of a glass tube (placed Sisal Hemp. (BUZZ. Imperial Inst., 1909, 7, 160-161.)-The following analyses of Sisal hemp from various districts in Africa are given : Sisal Hemp from- r- East Africa. ... Moisture -.. ... ... ... Ash ... a-hydrolysis (loss) ... ... P-hydrolysis (loss) ... ... ... Acid purification (loss) .'. . ... ... ... ... ... ... ... ... ... ... ... Cellulose ... ... ... ... Per Cent. 11.1 1.0 11.2 14.1 2.3 78.2 Uganda. ~ Per Cent. 7.9 0.7 9.2 11.3 0.7 80.3 Nyasaland. Per Cent. 9.2 0.5 8.6 11.1 0.35 80.9 A. R. T.

ISSN:0003-2654    

DOI:10.1039/AN9093400445

出版商:RSC    

年代:1909

数据来源: RSC

摘要:

THE ANALYST. 449 INORGANIC ANALYSIS. Estimation of Acids in Hydrogen Peroxide. 0. Luning. (Zeit. angew. Chem., 1909, 22, 1549-1550.)--The author has critically examined the points raised in a recent paper by Endemann (ANALYST, 1909,290). When the acidity of hydrogen peroxide is titrated with standard sodium hydroxide in the cold, in presence of phenolphthalein, the results are the same whether the titration be made directly or by titrating back an excess of the alkali first added. If, however, the peroxide be450 THE ANALYST. heated with the excess of alkali before titrating back, an apparent acidity is found, which is approximately twice as large as that determined by titration in the cold. The author points out that Endemann has interpreted these facts incorrectly. The acidity found by cold titration is really the correct one, whilst the excessive acidity found after heating with alkali is due to the production of a sodium perhydroxide which is neutral to phenolphthalein.The author has proved this synthetically, and has showlr that the neutral compound formed by heating the peroxide with excess of alkali, and neutralising in the cold, is rapidly decomposed by heating with a small excess of standard acid, after which the whole of the alkali neutralised by heating with the peroxide may be found again by titration. The investigation has also proved that hydrogen peroxide does not tend to form persulphuric acid in presence of dilute sulphuric acid, since the acidity remains constant under all the conditions employed. J. F.B. Attempt to Separate the Alkaline Earth Metals Electrolytically. J. S. Goldbaum and E. F. Smith. ( J . Amer. C7zenz. SOC., 1909, 31, 900-902.)-The decomposition value of strontium chloride is 0.16 volt higher than that of barium chloride, whilst the decomposition value of calcium chloride (free from magnesium) lies 0.13 volt higher than that of strontium chloride. The authors applied these facts to the electrolytic separation of barium from calcium, and of strontium from calcium, by electrolysing chloride solutions in the Hildebrand cell (ANALYST, 1907, 32, 428, and 1909, 34). The voltage used was 2.30 volts, being 0.07 volt above the decomposition - point of barium chloride ; the current was N.D,, = 0-02 ampBre. Some of the barium amalgam was always decomposed in the inner cell, leading to deposition of barium carbonate on the silver anode; for this reason the latter, before drying and weighing, was immersed in the standard hydrochloric acid used to titrate the barium hydroxide formed in the outer cell. I n the presence of 0.05 grm.of calcium chloride, the errors on 0.0345 grm. of barium (time, one and a half hours), and on the chlorine corresponding to it, are about 1 mgrm., the results for strontium being similar. Attempts to analyse mixtures containing all three metals in the same way gave only approximate results, the decomposition values of the chlorides in the mixture being closer together than those of the pure chlorides. Moreover, no sharp ‘( break ” in the current density could be observed when the whole of the barium salt had been decomposed.A. G. L. Quantitative Separation of Calcium from Magnesium. W. C. Blasdale. (J. Amer. Chem. SOC., 1909, 31, 917-922.)-For separating calcium from magnesium the author recommends the method of Richards, McCaffrey, and Bisbee, in which oxalic acid is added to the slightly acid solution, which is then slowly neutralised with ammonia. This procedure reduces the amount of magnesium occluded, and also gives a, coarsely granular precipitate. If the amount of magnesium present does not greatly exceed that of the calcium, a good separation can be effected by a single precipitation, provided that 0.6 grm. of the sample of mixed carbonates is taken; that, 1 grm. of oxalic acid is added to the boiling liquid, which should measureTHE ANALYST.451 300 C.C. and contain 3.5 grm. of ammonium chloride; and that after precipitation the liquid is neutralised with a 1 per cent. solution of ammonia, the addition of which should take five minutes, and then is allowed to stand for one hour. If the relative amount of magnesium is large, the precipitation should, if possible, be effected in two stages, during the first of which only sufficient oxalic acid to combine with the calcium is added, the remainder being added after ten minutes. If the amount of magnesium is ten times as great as that of the calcium, it is difficult to obtain exact results without a double precipitation. A. G. L. Estimation of Free Lime in Cement. R. Brandenburg. (Chenz. Zeit., 1909, 33, 880.)-A solution of ammonium bromide in absolute alcohol is distilled in presence of the cement, the ammonia evolved being regarded as a measure of the free lime in the cement.The alcohol used must be carefully freed from water, by distillation over lime and subsequent standing over ‘‘ activated ” aluminium, until evolution of gas can no longer be observed. Test analyses are cited showing that the method is accurate to within 0.1 per cent. of CaO. Ammonium bromide is not decomposed on boiling its alcoholic solution either alone or in presence of calcium carbonate. A. G. L. Determination of Antimony in its Sulphide Preparations. D. L. Howard and J. B. P. Harrison. (Pharm. Jozmc., 1909,83,147-148.)-The authors propose to convert the antimony sulphide into sodium metantimonate by fusion with sodium peroxide, the antimony salt being then reduced and estimated iodometrically, whilst the sulphur is estimated as sulphate.About 0-5 grm. of the substance is weighed out into a nickel crucible and,intimately mixed with sodium carbonate and sodium peroxide, 4 grm. of each being used for the golden sulphide, and 3 grm. for the black sulphide. The sodium carbonate acts as a restrainer, and prevents deflagration if free sulphur be present. The covered crucible is heated, very cautiously at first, until the contents have melted to a uniform mass. The contents of the crucible are extracted with a minimum quantity of boiling water and transferred to a beaker. The alkali is neutrslised by about 25 C.C. of concentrated hydrochloric acid, and 15 C.C. of acid are added in excess, together with 1 grm.of potassium chlorate to bring the antimony into solution. After heating to expel all free chlorine compounds, the solution is diluted to 250 C.C. For the estimation of the antimony, 100 C.C. of the solution are reduced by the addition of 1 grm. of powdered potassium metabisulphite, and the excess of sulphurous acid is eliminated by gentle ebullition. A few drops of phenol-phthalein are added to the sntimonious solution, and sodiurn hydroxide is gradually added until a permanent pink coloration is obtained. Finally a solution of tartaric acid is added until the precipitate formed is redissolved. After cooling, 3 grm. of solid sodium bicarbonate are added, and the antimony is estimated by titration with iodine (1 C.C. of iodine=0*006 grm. of antimony).The authors are of opinion that nntimoiciwn szdphzwatmiz should not contain less than 30 per cent. of antimony, and that the combined antimony and sulphur contents should amount to at least 95 per cent. of the whole. J. F. B.452 THE ANALYST Estimation of Chlorates. J. F. Virgili. ( A m . Chinz. anal., 1909, 14, 889- 294.)-The results of a number of experiments with the reagent described previously by the author (ANALYST, 1909, 69) are given, the main objects of the investigation being to ascertain whether chlorates can be detected and estimated in decomposing animal matters, and at what rate chlorates are reduced by such matters. The experiments were carried out on a mixture of 250 grm. of minced meat with 500 grm. of water, to which was added 0.5 grm.of potassium chlorate; a similar mixture, but without chlorate, was used for comparison. These mixtures mere kept at the ordinary temperature, and examined from time to time. I t was found that the quantity of chlorate did not appreciably diminish during the first ten days; on the nineteenth day it had decreased to 0.433 grm.; on the thirty-first day to 0.333 grm. ; on the forty-fifth day to 0.150 grm. ; and on the sixty-fifth day chlorate could no longer be detected i n the mixture. The mixture free from chlorate gave no coloration with the reagent. w. P. s. Estimation of Chlorine in Presence of Palladium, and Quantitative Estimation of Palladium by Reduction with Alcohol in Alkaline Solution. A. Gutbier and F. Falco. ( h i t . anal. Chem., 1909, 48, 555-559.)-Frenckclis method for the analysis of chloro-palladium compounds--e.g., (NH,),PdCl,-has been modified as follows : The concentrated aqueous solution of the salt is treated with sufficient pure sodium hydroxide to redissolve the precipitate first formed.Alcohol is then added, and the solution heated in a vigorously boiling water-bath until the alcohol has evaporated. A further quantity of alcohol is added, and evaporated as before, after which the liquid is heated to boiling for some time over a flame. The liquid is then allowed to cool somewhat, and decanted through a filter-paper, the precipitated palladium being repeatedly boiled out in the beaker with small quantities of water until the washings are free from alkali. The palladium is then transferred to the filter, which is dried at 100" C.and ashed. The palladium so obtained is ignited for a short time in a current of air, followed by hydrogen and finally by carbon dioxide, in which it is allowed to cool before weighing. Chlorine is estimated as usual in the filtrate and washings. The maximum error by this method is about 0.8 per cent. for either chlorine or palladium, but most of the results quoted are within 0.2 per cent. A. G. L. Gravimetric Estimation of Copper. P. B. Dallimore. (Pharm. JOZLI-n., 1909, 83, 271.)-Hypophosphorous acid reduces copper salts to metallic copper, which may be ignited to oxide and weighed. For example, 3 grms. of copper sulphate are gently heated on a water-bath with an excess of hypophosphorous acid diluted with an equal volume of water, the contents of the basin being kept well stirred.The copper sulphate need not be dissolved in water if it is roughly powdered. Finely divided metallic copper is precipitated in a few minutes, and the supernatant liquid is clear. The copper is filtered off, well washed first with hot water, then with a little alcohol and ether, dried in a current of air, and ignited to oxide. A typical experiment gave 3.085 grm. of CuSO4.5€I,O found, and 3.085 grm. taken=99*97 per cent. A. R. T.THE ANALYST. 453 Estimation of Copper by Means of Potassium Iodide and Arsenious Acid. F. M. Litterseheid-Hamm, (Apoth. i‘eit., 1909, 185 ; through J: Pharm. CAinL., 909, 30, 182.)-In the estimation of copper by the iodometric method tlie free iodine is estimated by means of arsenious acid. For an estimation, 50 C.C.of a solution of copper containing at least 0.1 grm. of copper, and free frorn nitric acid, is rendered slightly alkaline with ammonia, then treated with an excess of arsenious acid, followed by sufficient acetic acid to give a clear solution. Solid potassium iodide is uext added until blue colour disappears, and after standing for an hour the liquid is made up to 200 C.C. and filtered, and the excess of arsenious acid in 100 C.C. of the filtrate estimated by titration with TG iodine solution, after neutralisation with sodium bicarbonate. C. A. M. Simplified and Improved Iodometrie Estimation of Copper. E. V. Vide- gren. (Zeit. aiznl. Chem., 1909, 48,539-545.)-The copper is precipitated, according to Low’s method, by means of aluminium foil from sulphuric acid solution.Instead of then dissolving in nitric acid, the author prefers to dissolve the copper in a mixture of potassium chlorate and sulphuric and hydrochloric acids ; 20 C.C. of a 3.5 per cent. solution of potassiuni chlorate, and 20 C.C. of a mixture of 100 C.C. sulphuric acid (sp. gr. 1.40) with 900 C.C. of hydrochloric acid (sp. gr. l * l O ) , are sufficient for 1 grm. of copper. The solution is evaporated to remove chlorine and hydrochloric acid, diluted with water, and titrated as usual. If antimony or arsenic are present, an excess of sodium acetate is added before titrating. It is stated that tlie end-points obtained in this way are much sharper than those given with Low’s method of solution, The test results quoted are satisfactory.A. G. L. New Method for the Estimation of Iodides and Free Iodine. S. Bugarszky and B. Morvath. (Zeit. nnorg. Chem., 1909, 63, 184-196.)- The ilew method is based on the oxidation of the iodine to iodic acid by means of bromine-water, according to the equation : I, + 5Br2 + 6H20 = 2HI0, + 10HBr. The action icc reversible, and certain conditions of concentration, time, and temperature must be observed in order to effect the quantitative estimation. The oxidation is conducted in slightly acid solution, and the concentration of the iodine should not be greater then N/lOOO. For carrying out the estimation, a suitable quantity of the iodide solution, containing 10 to 12 mgrtn., is placed in a flask of 100 C.C. capacity with a narrow neck, the acidity is ,adjusted so as to he approximately N/100 when the flask is full, 50 C.C.of saturated bromine-water are added, and then water, until it reaches the bottom of the neck of the flask. The latter is placed in a beaker of boiling water and maintained at that temperature for one hour; the contents are then transferred to a larger flask, pumice is added, and the liquid boiled vigorously until the bromine is completely evaporated. This operation will require from four to Seven minutes’ boiling. The liquid is cooled, a few crystals of potassium iodide are added together with 5 C.C. of 2N sulphuric acid ; a few minutes are allowed to elapse for the liberation of the iodine, and this is finally titrated with thiosulphate.454 THE ANALYST. One-sixth of the iodine liberated represents the iodine in the original liquid.Provided the quantity of iodine to be estimated does not exceed 10 mgrm., the results are accurate within less than 1 per cent. The method, being extremely delicate, is admirably adapted for the estimation of iodides in mineral and sea waters. The presence of chlorides and bromides has no influence on the results. Commercial. bromine may be used, provided its iodine contents are previously estimated by a blank determination, In presence of iron and manganese salts, the method gives satisfactory results if the titration be made rapidly, and if no account be taken of the return of the blue colour after it has once been discharged by the thiosulphate. J. F. B. Rapid Method of Estimating Iron in Iron Ores. J.S. MacLaurin and W. Donovan. ( J . SOC. C h e m Ind., 1909, 28, 827-828.)-The following process is recommended for the estimation of iron in ores such as magnetites and hamatites, and, briefly, consists in roasting the ore, reducing the roasted ore by heating in hydrogen, dissolving the reduced ore in sulphuric acid in an atmosphere of carbon dioxide, and titrating the solution with permanganate. A weighed quantity of the finely ground ore is introduced into a hard glass bulb tube, and air is drawn through the tube while the bulb is heated to redness for a few minutes. The tube is then allowed to cool, the air-current is stopped, and a stream of hydrogen is sub- stituted, After heating for from ten to thirty minutes, according to the nature of the ore, the tube is again allowed to cool, and the reduced ore is shaken out into a flask containing about 2 grm.of sodium hydrogen carbonate and a little water. Any ore remaining in the tube is rinsed into the flask with dilute sulphuric acid. A current of carbon dioxide is passed into the flask, and the mixture is boiled for from five to twenty minutes, according to the ease with which the iron dissolves. The solution is then cooled while carbon dioxide is still being passed into the flask, and is next titrated with standard potassium permanganate solution. The process gives very concordant results. For instance, in estimating the iron in fifty-five samples of limonite, the greatest digerence in duplicate estimations was 0.22 per cent. of iron, and the average difference only 0.09 per cent.If the hydrogen be made from commercial zinc, it should be purified frorn antimony and arsenic, which interfere with the subsequent titration. The purification is most simply effected by passing the gas through a hard glass tube heated to redness by means of a long flat burner. The tube should be about 18 inches in length and about 0.5 inch in diameter, reduced to 0.1 inch for 4 or 5 inches to allow of the ready deposition of the antimony and arsenic. Any traces of these elements remaining in the gas are removed by passing the gas through a wash-bottle containing glass-wool saturated with chromic acid. The process is also applicable for the estimation of titanium in such iron ores as contain it. For this purpose hydrogen peroxide is added to the iron solution after the permanganate titration, and the quantity of titanium is ascertained by comparison with a standard solution of that substance. w.P. s. Dangers in the Transport of Ferro-Silicon. H. Le Chatelier. ( A m win., 1909, 15, 213 ; through Chenz. %reit. Rep., 1909, 33, 412.)-Lebeau has studied theTHE ANALYST. 455 gases evolved from different samples of fairly finely-divided ferro-silicon containing 58-90 per cent. of silicon. The volume of gases obtained from 1 kgrm. of the samples varied from 50 to 500 C.C. Arsenic hydrides were generally absent, but in one case constituted 50 per cent. of the total volume; hydrogen phosphide was present in nearly every case, in quantities of 4 to 74 per cent. ; the quantity of hydrogen varied from 1 to 100 per cent.I t should be remembered that the large blocks of ferro-silicon usually supplied would probably give off much smaller quantities of gases than the above, and also that cases of poisoning have so far only occurred with ferro-silicon containing about 50 per cent. of silicon, which has the property of crumbling to powder in air. A. G. L. Use of Dicyandiamidine for the Estimation of Nickel and its Separa- tion from Cobalt, Iron, Chromium, Zinc, Manganese, and Magnesium. H. Grossmann and W. Heilborn. (Paper communicated to the Seventh Interna- tional Congress of Applied Chemistry ; Chem. Zeit. , 1909, 33, 841-842, 851-852.)- Various modifications have been made in the methods of using the dicyandiamidine reagent since the previous papers were published (ANALYST, 1907, 32, 273, 394).The weighing of the nickel as anhydrous sulphate has been abandoned in favour of the weighing of the anhydrous salt, Ni(C,H5N,0),, obtained by drying the precipitate at 115-160" C. The precipitate is washed with a 3 per cent. solution of ammonia, as 100 C.C. of distilled water dissolve 0-0148 grm. at 15" C. In small volumes of solution (60 c.c.) precipitation is complete in fifteen minutes, and the solution need not be allowed to stand for six to twelve hours, as previously stated. Nickel can be precipitated free from cobalt if 10 to 20 C.C. of 10 per cent. solution of cane-sugar are added before the solution is made alkaline. From the filtrate, which shows a reddish-yellow to red colour, cobalt is precipitated as sulphide, as electrolysis yields a metal containing carbon.Iron is best held in solution by the addition of Rochelle salt, 10 to 15 grm. of the salt being used for each of iron. Small quantities of iron are conveniently separated as basic acetate before precipitating nickel. Chromiunz, if present as chromate, does not interfere with the precipitation of nickel; if present as a chromic salt, it may be oxidised to chromic acid with ammonium persulphate in dilute sulphuric acid solution ; or Rochelle salt may be added as for iron; or else acetic acid (or formic acid) may be added, and the solution boiled for an instant, the resulting chromic salt being stable in the cold towards alkalies. If the last procedure is used, chromium can be precipitated in the filtrate by simply diluting it and boiling for some time.Manganese is best kept in solution by the addition of citric acid and a small quantity (0.5 grm.) of hydrazine sulphate; it can be recovered from the filtrate by adding hydrogen peroxide, or, if cobalt is also present, by treatment with hydrogen sulphide at 100" C. The methods for separating zinc and alzuniizium from nickel have not been altered. Sinall quantities of magnesium can be kept in solution by the addition of Rochelle salt and ammonium chloride while the nickel is being precipitated; in the presence of larger quantities of ma,gnesium, however, it is necessary to precipitate the nickel first as sulphide, which is then dissolved and converted into the dicyandiarnidine salt. Rochelle salt nisy also be used if cadqium is present to hold the latter in456 THE ANALYST.solution during the precipitation of the nickel. Copper, mercury, and sdver, on the other hand, give insoluble salts with dicyandiamidine. The above methods of separation were successfully applied in the analysis of German silver, commercial nickel, nickel steel, and garnierite. I n the analysis of the latter, iron, nickel, cobalt, and manganese are first precipated together as sulphides, leaving magnesium in solution. Iron is next separated as basic acetate, and nickel precipitated in the filtrate as above. A. G. L. Study of the Phenolsulphonic Acid Method for the Estimation of Nitrates in Water: I. Composition of the Reagent and of the Reaction Product. E. M. Charnot and D. S. Pratt. ( J. Anier. Chenz. SOC., 1909, 31, 923- 928.)-The authors show that it is possible to identify the barium salts of the phenolsulphonic acids microscopically (cf, Obermiller, ANALYST, 1907, 32, 417).Barium orthomonosulphonate foruis long slender prisms with truncated ends ; the less soluble barium 2-4-disulphonate crystallises in clear, brilliant, colourless, highly refractive prisms and tables ; and the soluble barium paramonosulphonate forms rosettes of very slender white needles, having a silky lustre. The standard phenolsulphonic acid, as prepared for water analysis, consists of tho 2-4-disulphonic acid with small amounts of the pararnonosulphonic acid. The yellow colour obtained on adding alkali is due to a salt of a nitrophenolsulpbonic acid, and not to a salt of a nitrophenol or of picric acid. On adding the orthomonosulphonic acid to nitrates, diluting, and making alkaline, a dark green solution, with no shade of yellow, is obtained; the para acid is not acted on in the cold, but behaves like the ortho acid if heated in contact with the nitrate; the 2-4-disulphonic acid yields, either hot or cold, a pure yellow solution.Prolonged heating of the mono acids with nitrates yields greenish-yellow solutions, a part of the mono acids being converted into disulphonic acids by the heating. A. G. L. Estimation of Nitric Acid by Means of “Nitron.” C. Paal and A. Ganghofer. (Zeit. anal. Chew., 1909,48, 545-555.)-The paper is a criticism of the unfavourable results obtained by Hes (ANALYST, 1909,114) with nitrate solutions con- taining dextrin and gelatine. According to the present authors, Gooch or Neubauer (Munroe) crucibles should be used to collect the “ nitron ” nitrate, not paper. They quote results showing that, in presence of 2 grm.of dextrin in 100 C.C. solution, the results obtained for nitric acid are accurate to about 0.5 per cent. I n presence of 0.5 grm. of commercial peptone, results accurate to 0.2 per cent. are obtained if 20 to 25 drops of concentrated sulphuric acid are added before precipitation. With 0.5 grm. of gelatine present, the results are accurate to 0.1 per cent.; when 1 grrn. of dextrin was added, high results (2 per cent.) were obtained, and filtration was slow; preliminary removal of dextrin by means of tannic acid, followed by precipitation of the excess of the latter by neutral lead acetate, gave results 2 to 3 per cent.too low. Finally, the results obtained on meat extracts prepared in the cold were almost theoretical, except when the extract had begun to putrefy, in which case the results were low (7 per cent.); these meat extracts were treated with neutral lead acetate, boiled and filtered, before precipitation ; for putrefying extractsTHE ANALYST. 457 the authors recommend neutralisation with acetic acid before adding the lead acetate, to prevent formation of basic lead acetate, which is known to cause losses of nitric acid. A . G. L. Analysis of Sodium Sulphide. M. Tschilikin. (Zeit. anal. Chent., 1909, 48, 456-458.)-About 15 grm. of the sample are dissolved in 500 C.C. of air-free water, aud allowed to stand for twelve hours. The liquid is then filtered from iron sulphide, which is washed and ignited; the filtrate is made up to 1,000 C.C.Ten C.C. of this dilute solution are added to 50 C.C. +> iodine solution previously diluted with 200 C.C. of water ; the liquid is acidified by adding 10 C.C. of Tv sulphuric acid, and the excess of iodine titrated as usual with & sodium thiosulphate solution. The result obtained corresponds to the sum of sulphide and thiosulphate present in the sample. In another 10 C.C. of the diluted solution, sulphide only is precipitated by adding to a mixture of 5 grrn. cadmium carbonate, to precipitate the sulphide, with 100 C.C. of water and 10 C.C. Tn sulphuric acid; the precipitate is filtered off after fifteen minutes standing, washed, and the filtrate titrated with iodine and thiosulphate as above. Sulphide is obtained by difference; it may be checked gravimetrically by precipitating a copper sulphate solution, and weighing the precipitate as cuprous sulphide. The value now obtained corresponds to the thiosulphate present. A. G. L. Estimation of Tungstic Acid in Poor Ores. H. W. Hutchin and F. J. Tonks, (Eng. and Miit. JozLrn., 1909, 87, 1141; through Chenz. Zeit. h'ep., 1909, 33, 392.)-Five grm. or more of the ore are treated for half to three-quarters of an hour iu a px-celain dish on the water-bath with 20 C.C. of a 25 per cent. solution of sodium hydroxide (free from chlorine). After diluting, a little sodium peroxide is added to oxidise any sulphidcs present, and the liquid made up to 250 C.C. The solution is filtered, 200 C.C. of the filtrate me acidified with nitric acid, excess of ammonia is added, the whole boiled, the precipitate filtered off' and washed. The filtrate is acidulated with nitric acid, and about 20 C.C. of a solution of mercurous nitrate and a few drops of ammonia, are added. The whole is warmed, stirred, allowed to settle, the precipitate washed with a weak solution of mercurous nitrate, and ignited to tungstic trioxide, which may finally be treated with hydrofluoric acid. The solution of mercurous nitrate used for precipitation is prepared by heating 60 to 90 grm. of mercury for one and a half hours with 25 C.C. of concentrated nitric acid and 75 C.C. of water nearly to boiling, allowing to stand overnight in a warm place, and then diluting to 400 C.C. The method is not applicable to the analysis of scheelite. A. G. L.

ISSN:0003-2654    

DOI:10.1039/AN9093400449

出版商:RSC    

年代:1909

数据来源: RSC

摘要:

THE ANALYST. 457 APPARATUS, ETC. Drying Oven for Temperatures up to 460" C. A. Stahler. (Chcnz. h i t . , 1909, 33, 903.)-A hot-air oven is described, which is heated with an ordinary Bunsen burner, but which is designed to avoid the very great differences of Cernperature in various parts of the interior, which generally exist in the usual types458 THE ANALYST. of such ovens. It consists of a double-walled box, the inner walls being constructed of stout aluminium plate. The heat from the burner does not strike directly on the aluminium bottom, but is deflected and distributed by means of a copper plate. The hot gases pass up between the double walls of the box, the outside of which is constructed of asbestos millboard, and finally escape from a row of holes at the top.The oven is ventilated by means of two copper tubes, 15 mm. in diameter, passing through the double bottom of the box, and heated externally by the flame; similar openings are provided in the top of the oven. J. F. B. New Gas Burette. E. Hauser. (C'hem. Zeit., 1909, 33, 872.)-This consists of a pipette-shaped vessel closed at the top and having a capacity of 50 C.C. The upper and lower tubes, which hold 6 c.c., are graduated in corresponding divisions of & c.c., and can be closed by ground-in taps, the intermediate one of which, 2, is provided with radiating projections, so that it can be turned under water by means of a glass rod. Through the body of the vessel passes a platinum mire of 0.2 mm. in diameter, aud the outside ends of this are soldered to wires of the same metal of 0.5 mm.in diameter. I n making an analysis, the apparatus is completely filled with the gas and immersed in a cylinder of water. The tap 3 is then opened, and the burette placed at such a level that the meniscus within the lower tube shows the same xading on the scale as does the surface of the water in the cylinder on the corresponding scale on the upper tube. The tempera- ture is now taken, the tap 2 closed, the burette completely immersed in the water, and the combustion effected by an electric spark in the usual way. After standing for about five minutes the tap 2 is again opened, and the burette raised until the level of the liquid in the lower tube gives the same reading as that of the liquid outside the upper tube. The difference betweeu the readings on the lower scale before and after the combustion will then give the quantity of methane in the 50 C.C.of gas taken. The results thus obtained are shown to be in close agreement with those obtained with Le Chatelier's burette. C. A. 11. Apparatus for the Rapid Electrolytic Separation of Metals. H. J. S. Sand. (Chenz. Ti.ndc JOWIL., 1909, 45, 25.)-The apparatus devised by the author (ANALYST, 1908, 33, 395 and 411) has been modified so as to render it portable. A screw-cap cover is provided for the mercury contact; a clutch is added which renders it possible to stop the rotation of the anode without stopping the motor or interrupting the current; and the whole of the apparatus for measuring the potential, both that of the auxiliary electrode and that between the two main electrodes, is contained in a single box, a new form of horizontal capillary elec- trometer having been specially designed for this purpose.A. G. L. Graphite Cathode Dish. J. W. Turrentine. (Glzcnz. Nezos, 1909,100, 43-45.) -For electrolytic separations, where the highest accuracy is not essential, the expensive platinum dish cathodes may be replaced by dishes turned from blocks ofTHE ANALYST. 459 Acheson graphite (ANALYST, 1909, 386). The harder kinds of graphite, though less pure than the soft, are more suitable for turning, and give a more durable article. The graphite dishes are made impermeable to aqueous solutions by impregnating them with paraffin wax, and draining off the excess by heating at 110" C. in contact with absorbent paper.The di6culty of maintaining them at a constant weight forms the chief source of error involved in their use. The most satisfactory method as yet arrived at for drying the deposited metal before weighing consists in holding the dish in the Bunsen flame with the tongs, rotating it to effect uniform heating. A rotating graphite anode has also been designed to accompany the dish, and the apparatus would appear to be likely to make a satisfactory substitute for platinum in most branches of electro-chemical work. J. F. B. Purification of Mercury. J. H. Hildebrand. (J. Amer. Chem. SOC., 1909, 31, 933-935.)-The mercury to be purified is delivered from a separating funnel, the stem of which is slightly narrowed 0.5 cm. from the lower end. Over this end is bound with string a piece of rather closely-woven muslin.The stem of the funnel dips below the surface of a solution of mercurous nitrate contained in a vertical tube 1.5 m. long and 2 cm. in diameter, provided with a narrow delivery-tube at the lower end; this delivery-tube is bent upwards for a height of 25 cm. The muslin breaks the mercury up into a large number of fine streams, so that purification with this apparatus is exceedingly rapid. If the surface of the mercury is dirty, the last por- tions should not be allowed to enter the muslin bag. If the mercury is very impure, a preliminary purification by digestion with dilute sulphuric acid is advisable ; a piece of platinised platinum foil should be placed in contact with the mercury and acid. A. G. L. Notes on Quantitative Determinations by Means of the Microscope.E. M. Charnot. (Paper communicated to the Seventh International Congress of AppZied Chemistry.)-The author suggests that the material under examination be aistributed as evenly as possible in a drop of glycerine and water, and covered with a square cover-glass, care being taken to avoid air-bubbles, and to obtain a uniform distribution of the material. The preparation is then examined with the lowest power objective that will clearly show the adulterating material, the eye-piece being provided with a net micrometer or diaphragm, with a small, square opening. A count is next made of the number of foreign particles in a chosen area of the material under examination. Three or more mixtures, containing known percentages of the adulterant, are made up and examined in a similar manner, several counts of each being made.Upon a sheet of cross-section paper the percentages of adulterant are laid out as ordinates, and the numbers of foreign particles as abscissa The results obtained from the mixtures of known composition are then plotted out ; and if the material has been uniformly distributed, a straight line will connect these points with the zero-point on the scale. The position on this line of the figures obtained with the suspected sample will obviously indicate the percentage of adulteration.460 THE ANALYST. New Refractometer. (J. SOC. Chenz. Ind., 1909,28,773-775.)-J. Lewkowitsch describes the construction of the instrument, which is based on the Kohlrausch-Abbe method of determining the angle at which the limiting ray, entering the object under observation at grazing incidence, emerges from a cylinder quadrant made of French flint-glass of high refractive power. The instrument differs from the Pulfrich refracto- meter, which it resembles, in that a cylinder quadrant is used instead of the rectangular prism of the latter.The object to be examined, which may be a solid, liquid (contained in a special trough), or a gas, is placed on the polished horizontal surface of the quadrant. The monochromatic light used is thrown from a distance of 12 to 16 inches through the rectangular prism. As seen from the figure, the light falls into the substance under grazing incidence, and the limiting ray, after emerging from the cylinder quadrant, passes through a concave cylinder segment (of flint glass) in the telescope, and SO to the eye.The angle is read off from the arc, which is divided into one-quarter degrees, single minutes being read by means of the vernier, aud seconds by the micrometer screw. From the observed angle i and the known refractive index (N) of the cylinder quadrant, the [nID for the substance can be found by the formula: n=N sin i. All refractive indices between 1.000 and 1-733 can be observed. A table furnished with the instrument obviates the necessity of calculations in most cases. The refractometer is adjusted so that the angle for air is 34” 44’ 30”, and the 6 ‘ zero-point ” of the instrument is thus easily determined. In making the observation, by turning the rectangular prism downwards and sparking the hydrogen-tube provided, the refraction for the hydrogen line can be determined, and by thus changing the source of light the dispersion can be rapidly measured by turning the micrometer drum until the dividing line between the dark and illuminated fields passes again through the centre of the spider-web in theTHE ANALYST.461 telescope. The chief features of the instrument are that this dividing line is sharper and less curved than in other refractometers; also a wide range of angles can be observed, while the zero can be rapidly and easily checked. The quadrant is pro- vided with a water-jacket, so that observations can be made at any desired temperature. The instrument is manufactured by H. Heele, Berlin. A. R. T. Solvents for Use with the Munroe Crucible. 0. D. Swett. ( J . Anzer. Chem. SOC., 1909, 31, 928-932.)-1n dissolving precipitates out of the Munroe crucible (ANALYST, 1909, 298), hot concentrated sulphuric acid or hot hydrochloric acid, if used alone, cause considerable loss of platinum from the finely divided felt. This loss may be prevented entirely by adding ammonium salts, alkali nitrates, or nitric acid, to the concentrated or fuming sulphuric acid ; ammonium salts, except the nitrate, to the mixture of sulphuric and hydrochloric acids; and ammonium chloride, oxalic acid, or other reducing agent, to the hydrochloric acid used. A list of the best solvents for a large number of precipitates is given; e.g., a hot mixture of sulphuric acid with nitric acid or ammonium chloride dissolves barium sulphate. A. G. L.

ISSN:0003-2654    

DOI:10.1039/AN9093400457

出版商:RSC    

年代:1909

数据来源: RSC

摘要:

THE ANALYST. 461 GOVERNMENT REPORTS, ETC. BOARD OF AGRICULTURE AND FISHERIES. ANNUAL REPORT OF THE INTELLIGENCE DIVISION, Part I.: Proceedings under the Sale of Food and Drugs Acts, the Merchandise Marks Acts, the Fertilisers and Feeding Stuffs Act, and the Board of Agriculture Act, for the Year 1908.-The total number of samples taken during the year in England and Wales under the Sale of Food and Drugs Act was 95,249, including 44,396 samples of milk and 20,196 samples of butter. I n Scotland the total number of samples analysed was 8,827; of these, 4,282 were milk and 1,716 were butter. As in previous reports (see ANALYST, 1909, 79), tables are given showing the number of samples, both genuine and adulterated, analysed during 1908 in each county and borough in England, Wales, and Scotland.One thousand nine hundred and twenty samples were taken by officers of His Majesty’s Customs at various ports. These samples included 1,169 samples of butter, 38 of milk, 120 of condensed milk, 77 of cream, and 508 of margarine. The Report gives figures which justify the view that, especially in Scotland, informal samples afford a truer indication of the amount of adulteration in existence than do formal samples. For instance, about 10 per cent. of all samples taken formally were found to be adulterated, but in the case of informal samples 21 per cent. were adulterated. Several suggestions were received by the Board to the effect that the law should be amended so as to prohibit the sale of milk containing less than certain percentages of fat and solids-not-fat.I t is considered that any change adopted should enforce the prohibition by some means other than criminal proceedings, and that the change should be made part of a general amendment of the law relating to the sale of milk.462 THE ANALYST. The following numbers of factories were registered up to December 31, 1908, under the Butter and Margarine Act, 1907: Butter factories, 159; margarine factories, 30; factories of mixtures of butter and milk, 12. Various samples were taken at these factories by the inspectors, and a certain number were found to contain excess of water; the Board did not institute proceedings in any of the cases, but cautioned the manufacturers. Thirty-two fancy names for mixtures of butter with milk were approved. The total number of registered fancy names for margarine is now 2,384.The total number of samples of fertilisers analysed during the year was 1,477, and of feeding stuffs 1,934; 248 samples of fertilisers and 325 samples of feeding stuffs were reported to be of unsatisfactory quality, etc., and 42 applications were made for the Board‘s advice as to the institution of proceedings. In twelve cmes proceedings were taken, ten convictions being obtained, whilst two of the cases were dismissed. The contraventions in relation to which fines were inflicted corn- prised shoddy manure deficient in nitrogen, compound manure deficient in nitrogen and potash, barley-meal containing maize meal, shudes consisting of sawdust and gypsum, pollards containing gypsum, feeding-cakes deficient in albuininoids, etc.A number of inquiries were made during the year regarding the misuse of descriptions, and in some cases proceedings were instituted under the Merchandise Marks Acts. Convictions were obtained where American bacon had been sold as “ Irish,” and factory butter as ‘‘ creamery.” The following Regulations are published as an Appendix to the Report : STATUTORY RULES AND ORDERS, 1908. No. 964. Adulteration-Fertilisers and Feeding stuffs. THE FERTILISERS AND FEEDING STUFFS (METHODS OF ANALYSIS) REGULATIONS, 1908. DATED NOVEMBER 9, 1908. The Board of Agriculture and Fisheries, in pursuance of the provisions of the Fertilisers and Feeding StufTs Act, 1906, hereby make the following Regulations : COMMENCEMENT. 1. These Regulations shall take effect on the first day of January, 1909, and remain in force until altered or revoked by the Board of Agriculture and Fisheries.DEFINITIONF. 2. In these Regulations- ( ( The Act ” means the Fertilisers and Feeding Stuffs Act, 1906. “ Fertiliser ” means any article used for fertilising the soil. 6 6 Feeding stuff ” means any article used as food for cattle (as defined by the Act-Le., bulls, cows, oxen, heifers, calves, sheep, goats, swine, or horses) or poultry. Other expressions have the same respective meanings as in the Act.THE ANALYST. 463 METHODS OF ANALYSIS OF FERTILISERS. 3. The methods of analysis of a fertiliser for the purposes of the Act shall be as (i.) PREPARATION OF THE SAMPLE FOR ANALYSIS. (a) I n the case of powdered fertilisers in a dry, or moderately dry, condition, the sample shall be passed through a sieve with perforations about 1 mm.in diameter. Adventitious materials which cannot be conveniently crushed-e.g., fragments of metal in basic slag-shall be removed and allowed for. ( b ) Other substances which are dry enough to powder but which are not in a fine condition shall be pulverised until the sample passes through ti sieve with per- forations about 1 mm. in diameter. (c) Wool, hair, hoof, shoddy, and similar substances, shall be pulled apart and cut until in a fine condition ; or, if dry, they may be passed through a shredding machine. (d) Moist fertilisers which do not admit of being passed through a sieve shall be thoroughly mixed by the most suitable means. ( e ) I n the case of horn, shoddy, and other substances which gain or lose water during the process of pulverising, the proportion of water shall be estimated in the coarse and in the powdered condition respectively, and the results of the analysis of the powdered sample shall be calculated to the water content of the original coarse substance.(f) Crystalline or saline materials, such as sulphate of ammonia, nitrate of soda, or potash salts, may be prepared by being well mixed and rapidly ground in a stoneware mortar, the portion finally reserved for analysis being especially finely ground. (9) When the sample has been passed through the sieve and thoroughly mixed, or, if not passed through the sieve, has been thoroughly mixed, a part of it not being less than 100 grm. shall be placed in a stoppered bottle, and from this the portions for analysis shall be weighed.follows : (ii.) DETERMINATION OF MOISTURE (Loss ON DRYING). A weighed quantity of the sample shall be dried at 100' C. (iii.) DETERMINATION OF NITROGEN. The presence or absence of nitrates must first be ascertained. (a) Nitrogen in absence of Nitrates. (u) A weighed portion of the sample shall be transferred to a Kjeldahl digestion flask; 10 grm. of potassium sulphate and 25 C.C. of concentrated sulphuric acid shall be added, and the flask shall be heated until a clear liquid, colourless, or of light straw colour, is obtained. The operation may be accelerated by the addition of a small crystal of copper sulphate or a globule of mercury to the liquid in the digeetion flask. (p) The quantity of ammonia shall be determined by distillation into standard acid after liberation with alkali, and, where mercury has been used, with the addition also of sodium or potassium sulphide solution.464 THE ANALYSTo ( b ) Kitrogen when Nitrates are present.(u) A weighed portion of the sample shall be transferred to a Kjeldahl digestion flask ; 30 C.C. of concentrated sulphuric acid, containing 1 grm. of salicylic acid shall be added, and the flask shall be shaken so as to mix its contents without delay. The shaking shall be continued at intervals during ten minutes, the flask being kept cool, and then 5 grm. of sodium thiosulphate and 10 grm. of potassium sulphate shall be added. The flask shall be heated until the contents are colourless, or nearly SO. Copper sulphate or mercury may be used as above described in paragraph (iii.) (a) (a).(p) The quantity of ammonia shall be determined as above prescribed in paragraph (iii.) (a) (p). (c) Nitrogen in Form of Ammonium Salts. A weighed portion of the sample shall be transferred to a distillation flask, and the quantity of ammonia shall be determined as above prescribed in para- graph (iii.) (a) (@. (a) Nitrogen in Nitrrcies in the Absence of Ammonium Salts and of Organic Nitrogen. One grm. of the sample shall be placed in a, +litre Erlenmeyer flask with 50 C.C. of water. Ten grm. of reduced iron and 20 C.C. of sulphuric acid of 1.35 sp. gr. shall be added. The flask shall be closed with a rubber stopper provided with a thistle- tube, the head of which shall be half filled with glass beads.The liquid shall be boiled for five minutes, and the flask shall then be removed from the flame, any liquid that may have accumulated among the beads being rinsed back with water into the flask. The solution shall be boiled for three minutes more, and the beads again washed with a little water. The quantity of ammonia shall then be determined as above prescribed in paragraph (iii.) (a) (p). In cases in which the proportion of nitrates is small a larger quantity of the sample shall be taken. (e) Control Experiment in Dctewninntion of Nitrogen. The materials used in any of the methods described under this paragraph (iii.) shall be examined as to their freedom from nitrogen by means of a control experi- ment carried out under similar conditions, with the same quantities of the reagents which have been employed in the actual analysis, in the case of (a) 1 grm.of pure sugar being used in place of the weighed. portion of the sample. The quantity of standard acid used in the control experiment shall be deducted from the total quantity of acid found to have been neutralised in the distillation of the sample. (iv.) DETERMINATION OF PHOSPHATES. (a) Phosphates soluble in Water. I n the case of superphosphates, dissolved bones, and similar substances, 20 grm. of the sample shall be continuously agitated for thirty minutes in a, litre flask with 800 C.C. of water. The flask shall then be filled to the mark, and a.gain shaken, and the contents shall be filtered. Fifty C.C. of the filtrate shall be boiled with 20 C.C. of concentrated nitric acid, and the phosphoric acid shall be determined by the molybdate method prescribed below in paragraph (iv.) (d).In the case of fertilisers in which the proportion of phosphates soluble in water is small, a larger quantity of the filtrate prepared as above shall be taken.THE ANALYST. 465 ( b ) Phosphates soluble in the Prescribed Citric Acid Solutioiz. Five grm. of the sample shall be transferred to a stoppered bottle of about 1 litre capacity. Ten grm. of pure crystallised citric acid shall be dissolved in water, the volume shall be made up to 500 c.c., and the solution shall be added to the weighed portion of the sample in the bottle. To lessen the possibility of caking, the portion of the sample in the bottle may be moistened with 5 C.C. of alcohol or methylated spirit before the citric acid solution is added ; and in that case the volume of the citric acid solution shall be 495 C.C.instead of 500 C.C. The bottle shall be at once fitted into a, mechanical shaking apparatus, and shall be continuously agitated during thirty minutes. The solution shall then be filtered through a large '' folded " filter, the whole of the liquid being poured on the paper at once. If not clear, the filtrate shall be again poured through the same paper. Fifty C.C. of the filtrate shall be taken, and the phosphoric acid shall be determined by the molybdate method prescribed below in paragraph (iv.) (d). ( c ) Total Phosphoric Acid. A weighed portion of the sample, in which portion, if necessary? the organic matter has been destroyed by ignition, and the silica removed by appropriate means, shall be dissolved in nitric acid and boiled, the solution being made up to a definite bulk. The phosphoric acid shall be determined in an aliquot part of the solution by the molybdate method prescribed below in paragraph (iv.) (d).( d ) Molybdate Method. To the solution, which should preferably contain from 0.1 to 0.2 grm. of phosphoric oxide (P,O,), obtained as above described in paragraphs (iv.) (a), (b), or (c), 100 to 150 C.C. of molybdic acid solution, prepared as described below, or an excess of such solution-Le., more than is sufficient to precipitate all the phosphoric oxide present in the solution-shall be added, and the vessel containing the solution shall be placed in a water-bath maintained at '70" C.for fifteen minutes, or until the solution has reached 70' C. I t shall then be taken out of the bath and allowed to cool, and the solution shall be filtered, the phospho-molybdate precipitate being washed several times by decantation, and finally on the paper with 1 per cent. nitric acid solution. The filtrate and washings shall be mixed with more molybdic acid solution, and allowed to stand for some time in a warm place in order to ascertain that the whole of the phosphoric oxide has been precipitated. The phospho-molybdate precipisate shall be dissolved in cold 2 per cent, ammonia solution, prepared as described below, and about 100 C.C. of the ammonia solution shall be used for the solution and washings. Fifteen to 20 C.C.of .magnesia mixture, prepared as described below, or sn excess of such mixture-i.e., more than sufficient to precipitate all the phosphoric oxide present-shall then be added, drop by drop, with constant stirring. After standing at least two hours with occasional stirring, the precipitate shall be filtered off, washed with 2 per cent. ammonia solution, dried, and finally weighed as magnesium pyrophosphate. The filtrate and washings shall be tested by the addition of more magnesia mixture. ( e ) Preparation of Moly bdic Acid Solzstion. The molybdic acid solution shall be prepared as follows : One hundred and twenty-five grm. of molybdic acid and 100 C.C. of water shall466 THE ANALYST. be placed in a litre flask, and the molybdic acid shall be dissolved by the addition, while the fiask is shaken, of 300 C.C.of 8 per cent. ammonia solution, prepared a8 described below. Four hundred grm. of ammonium nitrate shall be added, the solution shall be made up to the mark with water, and the whole added to 1 litre of nitric acid (sp. gr. 1.19). The solution shall be maintained at about 35" C. for twenty- four hours, and then filtered. (f) Preparation of Naynesia Mixture. The magnesia, mixture shall be prepared as follows : One hundred and ten grm. of crystallised magnesium chloride and 140 grm. o€ ammonium chloride shall be dissolved in 1,300 C.C. of water. This solution shall be mixed with 700 C.C. of 8 per cent. ammonia solution, and the whole shall be allowed to stand for not less than three days, and shall be then filtered.(9) Preparation of the Ammonia Solutions. The 8 per cent. ammonia solution shall be prepared as follows : One volume of ammonia solution of sp. gr. 0.880 shall be mixed with 3 volumes of water. This solution shall then be adjusted by the addition thereto of more strong. ammonia solution or water as required until the sp. gr. of the solution is 0.967. The 2 per cent. ammonia solution shall be prepared as follows : One volume of 8 per cent. ammonia solution shall be mixed with 3 volumes of (v.) DETERMINATION OF POTASH. (a) Muriate of Potash free from Sulphates. A weighed portion of t,he sample (about 5 grm. in the case of concentrated muriate of potash, or 10 grm. in the case of low-grade muriate) shall be dissolved in water ; the solution shall be filtered (if necessary) and made up to 500 C.C.To 50 C.C. of the solution, placed in a porcelain basin, a few drops of hydrochloric acid shall be added, and also 10 or 20 C.C. (according to whether the portion weighed was 5 or 10 grm.) of a solution of platinum chloride containing 10 grm. of platinum per 100 C.C. After evaporation to a syrupy consistency on a water-bath, the contents of the basin shall be allowed to cool, and shall then be treated with alcohol of sp. gr. 0.864, being washed by decantation until the alcohol is colourless. The washings shall be passed through a weighed or counterpoised filter-paper, on which the precipi- tate shall be finally collected, washed with alcohol as above, dried at 100" C., and weighed. water. The precipitate is to be regarded as K,PtCl,.( b ) Salts of Potash containing Sulphates. A weighed portion of the sample (about 5 grm. in the case of concentrated sulphate of potash, or 10 grm. in the case of kainit or other lorn-grade salts) shall be boiled with 20 C.C. of hydrochloric acid and 300 C.C. of water in a +-litre flask. Barium chloride solution shall be cautiously added, drop by drop, to the boiling solution until the sulphuric acid is completely precipitated. Any slight excess of barium shall be removed by the addition of the least possible excess of dilute sulphuric acid. The liquid (without filtration) shall be cooled and made up to 500 C.C. A portion shall then be filtered, and 50 C.C. of the filtrate shall be treated as in paragraph (v.) (a), 10 or 20 C.C. of platinum chloride solution, as the case may be, being used.THE ANALYST.467 (c) Potash in Guanos, and Mixed Fertilisers. Ten grm. of the sample shall be gentlyignited in order to char organic matter, if present, and shall then be heated for ten minutes with 10 C.C. of concentrated hydro- chloric acid, and finally boiled with 300 C.C. of water. The liquid shall be filtered into a &litre flask, raised to the boiling-point, and a slight excess of powdered barium hydrate shall be added, The contents of the flask shall be cooled, made up to 500 c.c., and filtered. Of the filtrate, 250 C.C. shall be treated with ammonia solution and excess of ammonium carbonate ; and then, while boiling, with a little powdered ammonium oxalate, cooled, made up to 500 c.c., and filtered. Of the filtrate, 100 C.C.are to be evaporated in a platinum dish, and the residue heated, first in the air-bath, and then very gently over a low flame, till all ammonium salts are expelled, the temperature being carefully kept below that of low redness. The residue shall be treated with hot water, filtered if necessary, and the potash shall be determined in the filtrate as in paragraph (v.) (a), METHODS OF ANALYSIS OF FEEDING STUFFS. 4. The methods of analysis of a feeding stuff for the purposes of the Act shall (i.) PREPARATION OF THE SAMPLE. ( a ) If the sample is already in a fine condition-e.g., a meal-it shall be thoroughly mixed, and a portion for the determination of the moisture shall be a t once taken. ( b ) If the sample is not in a fine condition-e.g., a cake-it shall be carefully pulverised until the whole passes through a sieve with perforations from 2 to 3 mm.in diameter. I t shall then be thoroughly mixed, and a portion for the determination of the moisture shall be at once taken. (c) From the sample thus prepared a portion not less than 100 grm. in weight shall be taken and further powdered, if necessary, and passed through a sieve with perforations of about 1 mm. in diameter. (d) If the original sample is appreciably damp, or if for any reason the operations of pulverisation and mixing are likely to result in loss or gain of moisture, the moisture shall be determined in this portion, as well as in the sample prepared as in paragraph (i.) ( b), in order that the results of the analysis may be corrected to correspond with the sample in its original condition as regards moisture.(e) Materials which cannot be conveniently pulverised or passed through a sieve shall be thoroughly mixed and sampled by the most suitable means. (f) The prepared portion of the sample shall be placed in a, stoppered bottle, and from it the portions for analysis shall be weighed. (ii.) DETERXINATION OF MOISTURE (Loss ON DRYING). A weighed quantity of the sample shall be dried at 100" C. (iii.) DETERMINATION OF OIL. ( a ) A weighed quantity of the sample shall be placed in a Soxhlet thimble, which shall then be placed in the Soxhlet extraction-tube and extracted with washed, re-distilled ether. At the end of three to four hours the thimble shall be removed be as follows :468 THE ANALYST. from the Soxhlet tube, dried, and its contents finely ground in a small mortar pre- viously rinsed with ether, The substance shall then be returned to the thimble, the mortar being washed out with ether, and the extraction continued for another hour.After evaporation of the solvent the oil shall be dried at 1000 C., and weighed. The oil shall be re-dissolved in ether, and any undissolved matter shall be weighed and deducted. (b) In the case of samples containing saccharine matter-e.g., sugar meals-the weighed portion in the Soxhlet thimble shall be washed twice with water, and then dried, previous to the extraction. ( h a ) DETERMINATION OF ALBUMINOIDS. The percentage of albuminoids shall be ascertained by multiplying the percentage The determination of nitrogen shall be as follows : A weighed portion of the sample shall be transferred to a Kjeldahl digestion flask; 10 grm.of potassium sulphate and 25 C.C. of concentrated sulphuric acid shall be added, and the flask heated until a clear liquid, colourless, or of light straw colour, is obtained. The operation may be accelerated by the addition of a small crystal of copper sulphate or a globule of mercury to the liquid in the digestion flask. The quantity of ammonia shall be determined by distillation into standard acid after liberation with alkali, and, where mercury has been used, with the addition also of sodium or potassium sulphide solution. The materials used shall be examined as to their freedom from nitrogen by means of a control experiment carried out under similar conditions, with the same quantities of the reagents which have been employed in the actual analysis, 1 grm. of pure sugar being used in place of the weighed portion of the sample.The quantity of standard acid used in this control experiment shall be deducted from the total quantity of acid found to have been neutralised in the distillation of the sample. of nitrogen by 6.25. USE OF PRESCRIBED WEIGHTS. 5. In calculating the results of analyses the atomic weights adopted by the International Committee on Atomic Weights shall be employed. FORMS OF CERTIFICATES. 6. Every certificate which is affected by Regulation No. 3 of the Fertilisers and Feeding Stuffs (General) Regulations, 1906, and these Regulations, and which is dated on or after January 1, 1909, shall contain the following words : '' The analysis was made in accordance with the Fertilisers and Feeding Stuffs (Methods of Analysis) Regulations, 1908." w.P. s.THE ANALYST. 469 REPORT OF THE PRINCIPAL CHEMIST UPON THE WORK OF THE GOVERNMENT LABORATORY FOR THE YEAR ENDING MARCH 31, 1909, WITH APPENDICES. (ISSUED AS A PARLIAMENTARY PAPER, PP. 1-32.) The Report, as in previous years, is divided into three sections, dealing respec- tively with the work in connection with the Revenue Departments, with other Government Departments, and with the administration of the Food and Drugs Act and Fertilisers and Feeding Stuffs Acts. The total number of analyses and examina- tions made during the year was 176,922, against 191,034 for the preceding year. Of 4,347 samples of beer taken from publicans and retailers of beer, 352 were found to have been diluted with water, 5 were adulterated by the addition of saccharin, and 3 by the addition of a ‘( heading ” solution.Five hundred and fifty- nine samples of beer, wort, and materials used by brewers, were tested for the presence of arsenic. Of these, 30 were found to contain it in excess of the limits laid down by the Royal Commission on Arsenical Poisoning. Only 1 sample of malt, out of 114 samples examined, contained an amount exceeding the limit, the quantity of arsenic found in this case being one-twenty-fifth of a grain per pound. Of 278 samples of glucose, invert sugar, caramel, etc., none exceeded the limit. In addition to the above, 238 samples of mineral acids, chemicals, drugs, vinegar, etc., were also tested for this impurity. One thousand one hundred and eighty-five samples of imported butter were examined in accordance with the provisions of the Sale of Food and Drugs Act, 1899, and the Butter and Margarine Act, 1907.Of these, 429 contained boron preservative, and 203 added colouring matter. Only 9 of the samples contained water in excess of the legal limit. None of the samples contained foreign fat, and no samples of imported milk-blended butter were received for examination. Of the 505 samples of imported margarine analysed, 14 con- tained excess of water, and proceedings were taken against the importers ; there was no evidence of more than the legal quantity of butter-fat in any of the samples. I t is pointed out that the presence or absence of cocoanut oil must be ascertained before deciding that a Reichert-Wollny number exceeding 4 is evidence of an excess of butter-fat. Seventy-six samples of imported cream were examined : 33 contained boric acid, 6 both salicylic acid and boric acid, 5 ( ( hydroxyl,” and 1 boric acid and ‘( hydroxyl.” The amount of fat in the samples ranged from 10 to 48 per cent.The number of samples taken from premises where butter is blended or reworked, or where milk-blended butter is made, was 599; 33 of these samples of butter, 1 of milk-blended butter, and 9 of margarine, contained excess of water. One hundred and four samples of sheep-dips were submitted to the Board of Agriculture and Fisheries by makers who made application for the inclusion of the dip in the official (‘ Schedule of Efficient Dips ”; 51 were found to be of effective strength, 16 were deficient in active ingredients, and 37 required modification to produce a dip effective in the cure of sheep-scab.The number of samples referred to the Government Laboratory under the Sale of Food and Drugs Act was 120. No certificate was given in regard to 4 of the470 THE ANALYST. samples of milk, owing to the unsatisfactory condition of the sample or a leakage from the bottle. Out of the 116 samples examined, 100 agreed with the analyses of the Public Analysts. Nine samples of butter were referred as to admixture with foreign fat, but with regard to 3 of these cases the results of the Public Analyst could not be confirmed. I n 3 cases the charge was added water, and this was confirmed in 2 of the cases.Forty-two samples of milk were alleged to contain added water, but in 5 cases the charge could not be supported. Twenty-four samples were stated to be deficient in fat, but in 2 of these no deficiency was found. Eight sarnpleswere alleged to contain added water and to be deficient in fat; in 1 added water was not present, and in another there was no deficiency in fat. Boric acid was found in 2 samples, the certificates of the Public Analysts being confirmed, but formaldehyde was not detected in 2 samples alleged to contain it ; in issuing the certificates it was, however, pointed out that formaldehyde added to milk might not be detectable after the lapse of such a time as usually occurs between the taking of a sample and its reference to the Government Laboratory.There was a large increase in the samples examined under the Fertilisers and Feeding Stuffs Acts, the number being 35, against 5 in the preceding year. The samples comprised, among manures, basic slag, kainit, bone-meal, shoddy, and special fertilisers; and among feeding stuffs, crushed oats and beans, sharps and bran, pollards and shudes, meals, and feeding cakes. I n some instances the allegations made against the samples were of a striking character; for example, chick-pea meal containing no chick-pea, shudes consisting of sawdust and gypsum, and bone-meal consisting of asbestos and chalk. The remaining samples were deficient in one or other of the ingredients, or were otherwise impure-as, for example, crushed oats containing a considerable quantity of stones, and pollards adulterated with gypsum. w.P, s. On the Application of Formaldehyde to Meat. G. S. Buchanan and S. B. Sehryver. (Report to the Local Governmeizt Board, Food Report No. 9, 1909, l-l2.)-The Report discusses the various methods of applying formaldehyde to meat, such as the use of sprays and solutions, fumigation in safes, and treatment with formaldehyde vapour in the chilling holds of ships. A method for the estimation of formaldehyde is described, and the results of an examination of meat treated with formaldehyde are given. As regards the general question of the formaldehyde treatment of meat, the Report states that there are substantial objections to the presence of formaldehyde in foodstuff's, It is a, very powerful disinfectant ; it may retard digestion even when present in the food in coniparatively large dilution ; and it readily combines with the protein constituents of foods, forming a compound which is less digestible than the original substance. As some meat-suppliers and others have stated that no disinfectant can be discovered in meat which has been treated by fumigation with formaldehyde, an examination was made of a fore- quarter of chilled Argentine beef taken in London, with the assent of the importer, from the hold of a vessel in which formalin treatment had been employed.I t was found that formaldehyde could not only be recovered from various parts of the surface of the meat, but from parts below the surface. Where the muscular surfaceTHE ANALYST.471 was exposed to the vapour, the contamination was relatively large (1 in 3,500). A common depth of penetration into muscular tissue was 20 mm. under a thin super- ficial layer of connective tissue. Portions of the beef were also tested after cooking. Boiling and roasting appeared to reduce, or even remove, the formaldehyde. Grilling, however, seemed merely to make the formaldehyde penetrate farther into the substance of the meat. Cooked sausages made from the meat in question also contained formaldehyde. The results have a special significance as regards meat which is treated in formalin safes, Articles like meat, fish, kidneys, and other foods which expose a large surface in proportion to their weight, cannot be subjected to this form of formaldehyde fumigation without absorbing relatively large quantities of the disinfectant.Meat importers and traders should consider whether it is not desirable to limit the use of formaldehyde in ships to the adequate disinfection of the holds before the meat is introduced. The following process is described for the detection and estimation of formalde- hyde in meat : Ten grm. of the minced meat are heated for five minutes in a boiling water bath with water to every 10 C.C. of which have been added 2 C.C. of a 1 per cent. phenylhydrazine hydrochloride solution, In most cases where the amount of form- aldehyde is 1 part in 50,000 or less, this quantity of solution is sufficient. Where the concentrations are higher, larger quantities of liquid must be used. Thus, if the concentration of the aldehyde reaches 1 part in 5,000, 10 grm.of the meat are heated with 100 C.C. of water and 20 C.C. of the phenylhydrazine solution, After heating, the liquid is cooled and filtered through a plug of cotton-wool. To 1 2 C.C. of the filtrate are added 1 C.C. of 5 per cent. potassium ferricyanide solution and 4 C.C. of concentrated hydrochloric acid. In the presence of formaldehyde, a brilliant magenta-like coloration is produced, which reaches its full intensity after a few minutes’ standing, and keeps without deterioration for several hours. By comparing the colour with standards made with known quautities of formaldehyde, the amount of formaldehyde in any given meat sample can be ascertained. w. P. s. On the Use of Preservatives in Cream. d. M.Hamill. (Reports of Inspectors of Foods, 1909, No. 9, 1-35.)-Representations having been made to tho Local Government Board by traders that 0.25 per cent. of boric acid (the maximum limit recommended by the Departmental Committee on Preservatives, 1901) was insufficient for the preservation of cream, and that, in the conditions under which the cream trade has to be conducted, no lower limit than 0.5 per cent. of boric acid would suffice, the Board instructed the author to investigate the matter, and the result of his inquiries and experiments are given in this Report. As regards the effect of boric acid on health, it is pointed out that a good deal of research work has been carried out since the time of the inquiry by the Departmental Committee, and, while it cannot be said that unanimity of opinion exists amongst those who have investigated the subject, there remains a preponderance of opinion that boric acid and its com- pounds, in amounts such as may commonly be found in food, cannot safely be regarded as incapable of exerting a deleterious action upon health.The desirability Qf control, by prescription of limits and by compulsory declaration of the presence of preservative, will therefore be conceded. A description is given in the Report of the472 THE ANALYST. Rources of the cream-supply of the United Kingdom, of the conditions of the milk- supply to the creamery, of the methods of separation of cream, of the distribution of cream, etc. Whilst boron preservatives alone are most commonly used for the preservation of cream, admixtures of these preservatives with sodium salicylate or sodium benzoate are sometimes employed, and the author is informed that sodium fluoride is used in some cases as a cream preservative, as is also hydrogen peroxide.The experimental part of the inquiry dealt mainly with an investigation of the effect of different amounts of boric acid and boron compounds on the keeping properties of cream at relatively high temperatures, and under conditions approxi- mating to those under which the jug-cream trade is carried on. I t was found that 0.2 per cent. and 0.3 per cent. of boric acid were insufficient to preserve cream either at 65' F. or 71' F. for more than three or four days ; 0.4 per cent. and 0.5 per cent. of boric acid prevented the production of acid, but allowed the production of unpleasant flavour, from four to seven days, and of mould-growth after about six days, both at 65" F.and 71' F. A more effective preservative than pure boric acid consists of a mixture containing 7 grm. of alkali (Na,O) per 100 grm. of boric acid (H,BO,) ; 0.4 per cent. of this mixture is practically as effective as 0.5 per cent. at 65' F., but slightly less effective at 71" F. Cream may be preserved by either of these proportions for from four to seven days at temperatures up to 71" F. I t was also found that 0.5 per cent. of boric acid does not prevent the development of moulds in cream after from four to seven days. As a result of the inquiry, the following recommendations are made : 1. I n the interests of the public health and of the consumer, and also with, a view to removing difficulties which traders in cream are experiencing on account of present uncertainties, it appears desirable that effect should be given, subject to (2) below, to the recommendations made by the Departmental Committee on Preserva- tives, 1901; that the only preservative to be used in cream should be boric acid, borax, or mixtures of these boron preservatives; that a maximum limit of boron preservative, calculated as boric acid (H3BO3) should be prescribed; and that the presence of boron preservatives should in all cases be declared.These provisions should also apply to clotted cream. 2. An exception might, however, be made in respect of the use of hydrogen peroxide, the addition of which to cream might be permitted, provided that only traces were allowed to remain in the cream. 3.I t appears desirable that the question of issuing regulations on this matter should receive the Board's consideration, and that account should be taken of the following points : (a) The declaration of the presence of preservative to the purchaser, whether wholesale or retail, should in all cases be adequate, and the preserved cream as an article of commerce should be differentiated from cream which contains no added preservative. (b) In the case of boracised cream the maximum amount of boron preservative, calculated as boric acid (HsBOs), should be 0.4 per cent. from May to October inclusive, and 0.25 per cent. during the remainder of the year. (c) Cream in which boron preservatives are permitted, subjecb to the above limits, should in all cases contain at least 40 per cent.of milk-fat.THE ANALYST. 473 4. Having regard to the use of sweetening agents, such as saccharin, to conceal the sourness of cream and to impart an unnatural sweetness, it appears desirable that their presence should be notified to the purchaser. Notes on certain foreign and colonial regulations affecting the preparation and sale of cream are published as an addendum to the Report. They may be summarised as follows : United States of America.-The minimum limit for fat in cream varies in the different States. The lowest minimum limit is 15 per cent., and the highest 30 per cent. The addition of preservatives or foreign matter of any kind to cream is prohibited in most, if not all, of the States.Frunce.-There is no official definition or chemical standard in regard to the composition of cream, but the addition of any preservative or other chemical i s prohibited. All food products in the preparation of which antiseptics have been employed are considered as unfit for consumption, and are liable to seizure by the law of August 1, 1905. Germany.-There is no special Imperial law relating to cream apart from the general Food Law of 1879. Administrative districts may, however, by police ordinance prescribe limits for fat in cream, and in some districts a minimum limit of 10 per cent. of fat is prescribed, Cream containing preservatives would be dealt with under the Food Law. Several of the Federal States and a number of the larger towns have issued regulations prohibiting the addition of preservatives to cream.Victoria.-Cream must contain at least 40 per cent. of milk-fat, and the addition of any foreign substance, including preservatives, calcium sucrate, viscogen, or other thickening substance, is prohibited. w. P. s. Pure Food Act, 1908, New South Wales. (Gov. Gazette, N.S.W., July 28, 1909.)-The following regulations have been made under the powers conferred by the Act : Drugs.-Drugs which are not included in the latest addition of the British Pharmacopceia, but which are included in the British Pharmaceutical Codex, must comply with the descriptions and tests prescribed in the Codex. This regulation does not apply to certain ointments and liniments in so far as they are compounded with cotton-seed oil. Every pharmacist supplying a drug on a prescription which contains a direction that the drug may be prescribed a stated number of times shall writeon the prescription that he has supplied it, together with the date.Every mixture containing chloroform must bear a statement of the quantity of the latter present, unless the amount is below 0.25 per cent. Every package containing arsenic, mercury, various alkaloids, chloral hydrate, bromine, iodine, sulphonal, trional, veronal, paraldehyde, phenazone, phenacetin, acetanilide, and allied synthetic substances, must bear a label stating the name and quantity of the substance present. Proprietary medicines for internal use must not contain more than 15 per cent. (by volume) of ethyl alcohol and be free from methyl alcohol.I n any case where the quantity of alcohol exceeds 2.5 per cent. by volume, the quantity present must be stated on the label.474 THE ANALYST. MiZk.-Milk is defined as the normal secretion obtained from the udder of the healthy cow properly fed and kept, excluding that got the ten days immediately following on parturition. I t shall contain not less than 8.5 per cent. of solids-not-fat and 3.2 per cent. of milk-fat. Cream.-Not less than 40 per cent. of milk-fat must be present, and the cream must be free from all foreign substances. Skim Milk.-This is defined as milk from which part or all of the milk-fat has been removed. The fat-free liquid shall contain at least 8.8 per cent. of solids- not -fat. Butter.-A minimum limit of 82 per cent. of fat and a maximum limit of 16 per cent. of water, are prescribed. Common salt, harmless vegetable colouring matter, and not more than 0.5 per cent. of boric acid may be added, but foreign fats must be absent. Re.rzovated or Process Butter.-Besides conforming to the regulations relating to butter, each package of this article must be labelled Renovated Butter,” in type of specified size. Cheese.-Cheese must contain at least 50 per cent. of milk-fat in its water-free substance, and be free from foreign fats. The addition of ripening ferments, salt, and harmless vegetable colouring matter is allowed. Skim-milk cheese must contain not less than 10 per cent. of milk-fat in its water-free substance, and in other respects must comply with the general standard for cheese. Cream-cheese must contain at least 60 per cent. of milk-fat in its dry substance. Margarine.-This must be prepared from the fat of bovine animals, sheep, and pigs, and not from the fat of any other animal. Vegetable oils, vegetable colouring matter, and not more than 0.5 per cent. of boric acid, may be added. I t shall not contain more than 16 per cent. of water and not more butter-fat than is unavoidably introduced into it with milk used in its preparation. Each package containing margarine must be labelled plainly, and the words ‘‘ butter ” or L L butterine ” must not appear on the label. Condensed Milk.-Condensed, concentrated, or evaporated milk must contain a t least 25.5 per cent. of milk solids-not-fat, and 9.6 per cent. of milk-fat. Foreign substances, other than sugar, must not be present. Vessels containing it must be labelled, the label giving directions for making, by dilution, milk of composition at least equal to that of ordinary fresh milk, allowance being made for the presence of the sugar. Skimmed condensed milk must be labelled as such and contain not less than I t must not contain any foreign substance. 36-4 per cent, of milk solids-not-fat. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9093400461

出版商:RSC    

年代:1909

数据来源: RSC